BIOMEP 2017 - Conference on Bio-Medical …biomep.teiath.gr/2017/docs/BIOMEP_2017_Book of...

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BIOMEP 2017 - Conference on Bio-Medical Instrumentation and

related Engineering and Physical Sciences

Organized by the

Department of Biomedical Engineering,

Technological Educational Institute (TEI) of Athens,

Athens University of Applied Sciences / Greece

BOOK OF ABSTRACTS

Conference referred and accepted papers will be published by the Journal of Physics: Conference Series (IOP Publishing)

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Preface The International Conference on Bio-Medical Instrumentation and related Engineering and Physical Sciences (BIOMEP 2017) was organized by the Department of Biomedical Engineering of the Technological Educational Institute (TEI) of Athens, Greece, on October 12-13, 2017.

The scope of the conference was to provide a forum on the latest developments in Biomedical Instrumentation and related principles of Physical and Engineering sciences. Scientists and engineers from academic, industrial and health disciplines were invited to participate in the Conference and to contribute both in the promotion and dissemination of the scientific knowledge.

BIOMEP 2017 - Committees Conference Chair: I. Valais (Chair), TEI of Athens, GR I. Kandarakis (co-Chair), TEI of Athens, GR

Organizing Committee:

I. Kandarakis (Chair), TEI of Athens, GR S. David, TEI of Athens, GR G. Fountos, TEI of Athens, GR I. Kalatzis, TEI of Athens, GR G. Loudos, TEI of Athens, GR C. Michail, TEI of Athens, GR I. Valais, TEI of Athens, GR

Scientific Committee: G. Fountos (Chair), TEI of Athens, GR D. Arotaritei, University of Medicine and Pharmacy, RO P. Asvestas, TEI of Athens, GR A. Bakas, TEI of Athens, GR N. Belcari, University of Pisa, IT D. Cavouras, TEI of Athens, GR L. P. Coelho, Polytechnic Institute of Porto, PT S. David, TEI of Athens, GR E. Eftathopoulos, University of Athens, GR C. Fountzoula, TEI of Athens, GR A. Gaitanis, Biomedical Research Foundation Academy of Athens, GR P. Giannakopoulos, Piraeus University of Applied Sciences, GR D. Glotsos, TEI of Athens, GR I. Kalatzis, TEI of Athens, GR M. Kallergi, TEI of Athens, GR I. Kandarakis, TEI of Athens, GR G. Kagadis, University of Patras, GR G. Kaltsas, TEI of Athens, GR N. Kalyvas, TEI of Athens, GR C. Kappas, University of Thessaly, GR P. Karaiskos, National and Kapodistrian University of Athens, GR

http://www.bme.teiath.gr/en_index.html

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G. Kastis, Acting Director of Research Center of Pure and Applied Mathematics, Academy of Athens, GR A. Konstantinidis, Christie Hospital NHS Foundation Trust, UK G. Kontaxakis, Universidad Politécnica de Madrid, ES L. Kostaridou, University of Patras, GR S. Kostopoulos, TEI of Athens, GR E. Kounadi, Ministry of Health, GR V. Koukou, University of Patras, GR P. Liaparinos, TEI of Athens, GR G. Loudos, TEI of Athens, GR D. Mantas, Medical School, University of Athens, GR D. Nikolopoulos, Piraeus University of Applied Sciences, GR N. Martini, University of Patras, GR C. Michail, TEI of Athens, GR G. Panayiotakis, University of Patras, GR P. Platoni, Attikon Hospital, GR A. Ploussi, Medical Physicist, GR M. J. Rodríguez Alvarez, Universidad Politécnica de Valencia (i3M), ES C. Rotariu, University of Medicine and Pharmacy, RO G. Sakelaropoulos, University of Patras, GR L. Scalise, Universita' Politecnica delle Marche, IT I. Sianoudis, TEI of Athens, GR A. Skouroliakou, TEI of Athens, GR R. Speller, University College London, UK B. Spyropoulos, TEI of Athens, GR I. A. Tache, University "Politehnica" of Bucharest, RO A. Taibi, Universita degli studi di Ferrara, IT D. Triantis, TEI of Athens, GR S. Tsantis, Thriasio General Hospital, GR H. Tsoumpas, University College London, UK I. Valais, TEI of Athens, GR D. Vattis, TEI of Athens, GR E. Ventouras, TEI of Athens, GR E. Zych, University of Wroklaw, PL

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Thursday 12, October 2017

9:15 – 9:30 Welcome Speeches

Prof. M. Venetikou, Rector of TEI of Athens, Greece

Prof. S. Athinaios, Dean, Faculty of Technological Applications, TEI of Athens, Greece

Prof. I. Kandarakis, Head of the Department of Biomedical Engineering T.E.

Oral Sessions (9:30 – 18:30)

9:30 – 11:00 Session 1. Medical Imaging and Radiation Monitoring Session Chairpersons: G. Fountos, S. David

9:30 - 9:45 Digital Breast Tomosynthesis - New technique in Breast Imaging Y. Sdralis

KMS medical Corresponding author: Y Sdralis, [email protected]

Keywords: Mammography, Digital Breast Tomosynthesis (DBT)

Mammography is the most common imaging exam during the last 30 years for screening and

diagnosis of breast cancer (which is the No1 cancer type among women population). Typically during a

2D Mammography exam, each breast is twice positioned and briefly compressed for a few seconds to

acquire four X-ray images. One of the biggest challenges in conventional 2D mammography are

overlapping tissue structures. Overlapping tissue structures cause structural noise that may lead to the

following unwanted situations: Obscure findings causing lesions to be missed which cause decreased

sensitivity, Overlapping tissue structures simulate a presence of a lesion that does not actually exist

which cause decreased specificity.

To this presentation we will describe the basic technical characteristics of the 3D Digital Breast

Tomosynthesis (DBT) which is an advanced new imaging technique. The breast is scanned over an arch

of 15-50 degrees, during which multiple X-ray images are taken to create a 3D image that shows

tissue structures in more detail. The 3D image acquired by the tomosynthesis sequence can be scrolled

through slice by slice and to resolves overlapping tissue structures. The radiation dose associated with

one-view DBT acquisition is slightly higher compared to 2D acquisition but still remains well below the

current diagnostic reference levels for one-view mammography. In the near future the DBT has the

clinical advantages to replace the conventional 2D Mammography especially to the women with dense

breast tissue.

mailto:[email protected]

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9:45 - 10:00 Evaluation of Scintillation Response of ZnSMn Quantum Dots under X-ray irradiation G. Saatsakis1, I. Valais2, C. Michail2, C. Fountzoula3, G. Fountos2, V. Koukou2, N. Martini2, N.

Kalyvas2, I. Kandarakis2, G. S. Panayiotakis1

1Department of Medical Physics, Medical School, University of Patras, Greece 2Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece

3Department of Medical Laboratories, Technological Educational Institute of Athens, Greece Corresponding Author: I Valais, [email protected] Keywords: Scintillation Quantum Dots (stQDs), Luminescence Efficiency (LE), Polymer film

Quantum Dots are semiconductor nanocrystals, with their optical properties controlled by their size,

shape and material composition. The aim of the present study is to examine the scintillation properties

of Manganese Doped Zinc Sulfide (ZnSMn) Quantum Dot nanocrystals under X-ray irradiation. ZnSMn

Quantum Dots (QDs), with typical diameter of ZnS dots of 13−20nm (also called scintillation QDs,

stQDs), where developed and acquired by Mesolight Inc. The initial stQD sample was a solution of

75mg of Zn2SiO4:Mn (Lumilux 51140) dissolved in 100μL of Toluene, having a concentration of 75%

w/v. Parameters such as the Luminescence Efficiency-LE (light energy flux over exposure rate) and the

light spectral compatibility to electronic optical sensors (Effective Efficiency) were investigated under

X-ray excitation in the energy range from 50 to 130 kVp. LE was higher than that exhibited by a 157mg

Zn2SiO4:Mn powder phosphor screen prepared in our laboratory by polymer based screen preparation

technique. The emission spectrum of the stQDs, exhibited a narrow peak (~580nm) in the yellow

range, is well matched with the spectral sensitivities of the optical photon detectors often employed in

radiation detectors. The incorporation stQDs in polymer thin film screens will enable the production of

high resolution X-ray sensors.


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10:00- 10:15 Performance Characteristics of a Personal Gamma Spectrometer based on a SiPM array for Radiation Monitoring Applications E. Kefalidis1, I. Kandarakis1, 2, S. David1, 2

1Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece

2Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of

Biomedical Engineering, Technological Educational Institute of Athens, Greece Corresponding Author: S David, [email protected] Keywords: Radiation monitoring, SiPM, GAGG:Ce, Compact Spectrometers Due to the increased radiation pollution in the environment as a result of the often nuclear accidents

taking place around the world, the need for efficient, reliable, smart and handheld radiation

measurement systems has been born especially in daily routine. In this study it is evaluated the

angular response of two crystal non-pixelated Gd3Al2Ga3O12:Ce (GAGG:Ce) scintillators with

dimensions at 10x10x10 mm3 & 10x10x20 mm3 under 137Cs isotope emitting at 662 keV coupled to a

4x4 discrete silicon photomultiplier array (SiPM). A symmetric resistive voltage division matrix was

applied reducing the array 16 outputs to 4 analog position signals which digitized by a 4 Channel 12 bit

250 MS/s desktop waveform digitizer. The number of the evaluated angles set at 5 (0o, 45o, 90o, 135o,

180o) and a variety of measured values are presented (energy resolution, sensitivity, figure of merit

etc). The encouraging results such as 9% of energy resolution and figure of merit about 4.11 for

10x10x10 mm3 & 4.43 for 10x10x20 mm3 crystal, prove that this system could build up to a compact

radiation sensor for integration into mobile applications.

Acknowledgement

«This research is implemented through IKY scholarships programme and co-financed by the European

Union (European Social Fund - ESF) and Greek national funds through the action entitled

”Reinforcement of Postdoctoral Researchers”, in the framework of the Operational Programme

”Human Resources Development Program, Education and Lifelong Learning” of the National Strategic

Reference Framework (NSRF) 2014 – 2020».


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10:15 - 10:30 Comparative Evaluation of Cesium Iodine Scintillators Coupled to a Silicon Photomultiplier (SiPM): Effect of Thickness and Doping on the Scintillators E. Monachesi1, A. Dezi1, M. D’Ignazio1, L. Scalise2, L. Montalto2, N. Paone2, D. Rinaldi3, G. Loudos4,

S.David4

1Faculty of Engineering, Università Politecnica delle Marche, Ancona, Italy 2Dipartimento di Ingegneria Industriale e Scienze Matematiche, Università Politecnica delle Marche, Ancona, Italy 3Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio 4Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece Corresponding Author: S David, [email protected] Keywords: Inorganic scintillators, SiPM, CsI:Tl, CsI:Na Cesium Iodide (CsI) crystals are referred as the ‘state of art’ scintillator materials used in most of

Nuclear Medical Imaging systems because of their high light yield outputs and low cost. In this work, a

characterization in terms of energy resolution, photo-fraction, sensitivity as well as the figure of merit,

of CsI:Na and CsI:Tl scintillators, are presented. A set of samples with 9 mm2 of cross section and a

thickness ranging from 1 to 7 mm have been tested on a silicon photomultiplier (PM3350) using two

different radioactive sources: 133Ba (0.081 MeV and 0.356 MeV) and 137Cs (0.662 MeV). The best

energy resolution values were achieved by the 3x3x7 mm3 CsI:Na at 0.662MeV equal to 8%. For the

CsI:Tl scintillator with the same dimensions the energy resolution was equal to 8.2%. At 0.081MeV the

best energy resolution was recorded for crystals with 3x3x5 mm3 dimensions equal to 18.9% for CsI:Na

and 24.9% for CsI:Tl. Results were compared to a reference NaI:Tl 3x3x5 mm3 and 3x3x10 mm3 as well

as with previous published data.

Acknowledgment

This work was partially supported by an Erasmus Plus Traineeship educational program between the

Department of Biomedical Engineering of TEI of Athens and the Università Politecnica delle Marche,

Ancona.


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10:30 - 10:45 Structural Characterization and Absolute Luminescence Efficiency Evaluation of Gd2O2S High Packing Density Ceramic Screens Doped with Tb3+ and Eu3+ for further Applications in Radiology A. Dezi1, E. Monachesi1, M. D’Ignazio1, L.Scalise2, L. Montalto2, N. Paone2, D. Rinaldi3, P. Mengucci3

G.Loudos4, A. Bakas5, C. Michail6, I. Valais6, C. Fountzoula7, G. Fountos6, S. David4, 6

1Faculty of Engineering, Università Politecnica delle Marche, Ancona, Italy 2Dipartimento di Ingegneria Industriale e Scienze Matematiche, Università Politecnica delle Marche,

Ancona, Italy 3Dipartimento SIMAU, Università Politecnica delle Marche, Ancona, Italy 4Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece 5Department of Radiology & Radiation Therapy, Technological Educational Institute of Athens, Greece 6Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of

Biomedical Engineering, Technological Educational Institute of Athens, Greece 7Department of Medical Laboratories, Technological Educational Institute of Athens, Greece

Corresponding Author: S David, [email protected] Keywords: Inorganic phosphors, Luminescence efficiency, Gd2O2S:Tb, Gd2O2S:Eu

Rare earth activators are impurities added in the phosphor material to enhance probability of visible photon emission during the luminescence process. The main activators employed are rare earth trivalent ions such as Ce+3, Tb+3, Pr3+ and Eu+3. In this work, four terbium-activated Gd2O2S (GOS) powder screens with different thicknesses (1049 mg/cm2, 425.41 mg/cm2, 313 mg/cm2 and 187.36 mg/cm2) and one europium-activated GOS powder screen (232.18 mg/cm2) were studied to investigate possible applications for general radiology detectors. Results presented relevant differences in crystallinity between the GOS:Tb doped screens and GOS:Eu screens in respect to the dopant agent present. The AE was found to rise (i) with the increase of the X-ray tube voltage with the highest peaking at 110kVp and (ii) with the decrease of the thickness among the four GOS:Tb. Comparing similar thickness values, the europium-activated powder screen showed lower AE than the corresponding terbium-activated.

Acknowledgment

This work was partially supported by an Erasmus Plus Traineeship educational program between the

Department of Biomedical Engineering of TEI of Athens and the Università Politecnica delle Marche,

Ancona.


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10:45 - 11:00 Experimental Evaluation of Gd3Al2Ga3O12: Ce (GAGG: Ce) Single Crystals Coupled to a Silicon Photomultiplier (SiPM) under High Gamma Ray Irradiation Conditions

A. Metallinos1, E. Kefalidis1, I. Kandarakis1, 2, S. David1, 2


2Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of

Biomedical Engineering, Technological Educational Institute of Athens, Greece

Corresponding Author: S David, [email protected] Keywords: Inorganic phosphors, SiPM, GAGG:Ce, Compact Spectrometers

Cerium (Ce) ion doped scintillators are of high interest in Medical Imaging and radiation monitoring

detectors, due to their very fast response and emission characteristics. In this study, a series of

measurements regarding the energy resolution, photofraction, sensitivity, as well as the figure of

merit, of Gd3Al2Ga3O12:Ce (GAGG:Ce) scintillator crystals, are presented. All GAGG:Ce crystals have a

surface area of 3x3 mm2 with varying thicknesses from 4 up to 20 mm (4, 5, 6, 8, 10, 15 and 20 mm).

These crystals were exposed to γ radiation, using two different radioactive sources: 137Cs (0.662 MeV)

and 60Co (1.173 MeV and 1.332 MeV). Each crystal was measured individually and was optically

coupled to a KETEK PM3350 SiPM, an optical sensor with high gain, suitable to operate in room

temperature. The digitization of the pulses was accomplished using CAEN DT5720 desktop digitizer

and its corresponding digital pulse processing (DPP) firmware. Each measurement was performed in a

light-tight box and had duration of 30 min. The best energy resolution value was measured for the

GAGG:Ce 3x3x15 mm3 equal to 3.9% at 1.332 MeV. Results were evaluated and compared to previous

published data.

Acknowledgement

«This research is implemented through IKY scholarships programme and co-financed by the European




Reference Framework (NSRF) 2014 – 2020».


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11:30 – 13:00 Session 2. Image Processing and Reconstruction Session Chairpersons: A. Gaitanis, G. A. Kastis

11:30 – 11:43 Towards a Standardization Method for Textural Analysis in Preclinical FDG PET images A. Gkolfinopoulou1, G. A. Kastis2, 3, A. Gaitanis4

1Technological Educational Institute of Athens, Department of Biomedical Engineering, Greece. 2Research Center of Mathematics, Academy of Athens, Greece. 3Institute for Nuclear & Radiological Sciences & Technology, Energy & Safety, National Center for

Scientific Research “Demokritos”, Athens, Greece 4Biomedical Research Foundation of the Academy of Athens (BRFAA), Greece.

Corresponding Author: A Gaitanis, [email protected] Keywords: Textural analysis, Textural features, First order features, Second order features (GLCM), 18F-FDG-PET, Preclinical Imaging

FDG-PET textural analysis is a new method for assessing tumor heterogeneity. Various papers have

been published but there are still a lot of technical details which must be addressed in order for this

method to be established in clinical work. In clinical FDG-PET it is difficult to correlate image

characteristics with tumor biology and hence the repeatability and reliability of the textural methods

cannot be easily evaluated. This drawback can be overcome in preclinical imaging where animals are

used for the study of cancer diseases. For the standardization of textural analysis methods in micro

PET/CT, an image quality (IQ) phantom was employed. Small animal images, with different cancer

types and image reconstruction parameters were also analyzed. For textural analysis, various first

order (FOF) and second order features (GLCM) were employed and software were developed in order

to calculate those features. The results were statistically analyzed using the percentages of coefficient

of variance (%COV) and the difference with respect to the mean value (%Diff) parameters. For the

phantom, image reconstruction with high regularization level, 4 subsets and 9 iterations found to

produce images with low variation for entropy, skewness, kurtosis, inverse difference normalized and

inverse difference moment normalized. The textural features demonstrated dependence on the size of

the rods of the phantom. Moreover, the animal results demonstrated very small variability for entropy,

correlation and inverse different moment features.


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11:43 – 11:56 Validation of Recent Developments in STIR Library for GE SIGNA PET/MR Scanner Using Real Data P. Wadhwa

1, 2, K. Thielemans

3, C. Tsoumpas1

1University of Leeds, Div. of Biomedical Imaging, Leeds, United Kingdom of Great Britain and

Northern Ireland, UK 2Imanova UK, Centre for Imaging Science, London, United Kingdom of Great Britain and Northern

Ireland 3University College London, Institute of Nuclear Medicine, London, United Kingdom of Great Britain

and Northern Ireland, UK

Corresponding Author: C Tsoumpas, [email protected] Keywords: STIR, PET/MR, Image Reconstruction Software for tomographic image reconstruction (STIR: http://stir.sf.net) is an open source C++ library

that is capable of reconstructing emission tomography data. This work validates the recent

developments in STIR library to read and reconstruct the data extracted from the GE SIGNA PET/MR

scanner.List-Mode (LM) datasets were collected as a part of a phantom experiment with the GE SIGNA

PET/MR scanner. The datasets were converted into STIR readable sinograms using recently developed

libraries that allows binning the LM data acquired from this scanner. Validation of the reconstructed

images was done by comparing the OSEM images reconstructed with the same settings using the

company’s reconstruction software. Images were compared by voxel-wise subtraction. Regions of

interest (ROIs) near and on the boundary of the myocardium and the liver were also analysed. The

comparison displayed a difference of 5% between the images further from the boundary and a

difference of ±11% and 13% respectively near the boundaries of myocardium and liver which were the

most active regions in the phantom. This presentation will provide the framework for reconstructing

data using STIR for this scanner and will include a comparison of the reconstructed images from STIR

and with the company’s software.

Acknowledgements:

-Funded by MRC (Medical Research Council), UK under Grant Number: MR/M01746X/1

-Floris Jansen, Chief Engineer, PET/MR at GE Healthcare, University of Cambridge, UK

-Michel Tohme, PET/MR Engineering, GE Healthcare, University of California, USA

-S. Vandenberghe, Gent University, Medical Image and Signal Processing Group, Gent, Belgium

-M. Koole, KU Leuven, Nuclear Medicine & Molecular Imaging, Leuven, Belgium

-G. Delso, GE Healthcare, Cambridge, United Kingdom of Great Britain and Northern Ireland

-O. Bertolli, University College London, Institute of Nuclear Medicine, London, United Kingdom of

Great Britain and Northern Ireland

-D. Deidda, University of Leeds, Div. of Biomedical Imaging, Leeds, United Kingdom of Great Britain

and Northern Ireland

-E. D'Hoe, Gent University, Medical Image and Signal Processing Group, Gent, Belgium

-W.Hallett, Imanova UK, Centre for Imaging Science, London, United Kingdom of Great Britain and

Northern Ireland

-D.Buckley, University of Leeds, Div. of Biomedical Imaging, Leeds, United Kingdom of Great Britain

and Northern Ireland

-R.Gunn, Imanova UK, Centre for Imaging Science, London, United Kingdom of Great Britain and

Northern Ireland


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11:56 - 12:09 Ray Tracing Generalized Backprojection-Filtration Algorithm for Positron Emission Tomography S. Sánchez1, A. Iborra1, P. Conde1, J. M. Alvárez-Gómez1, A. Soriano1, A. González-Montoro1, A.

Aguilar1, G. Cañizares1, E. Lamprou1, S. Iranzo1, L. Moliner1, F. Sánchez1, A. J. González1, J. M.

Benlloch1, M. J. Rodríguez-Álvarez1

1Institute for Instrumentation in Molecular imaging (i3M), Valencia, Spain 2Laboratory of Medical Information Processing (LaTIM - INSERM UMR 1101), Brest, France.

Corresponding Author: S Sánchez , [email protected] Keywords: Ray tracing generalized backprojection-filtration algorithm, Filtered Back projection, Maximum Likelihood Expectation Maximization, List Mode Ordered Subset, Line of Response, Butterworth filter and Median Filter A direct ray tracing algorithm has been proposed under the development of a dedicated brain PET

insert scanner, based on monolithic scintillation crystals. This algorithm avoids the use of histograms

or system matrices, as in the case of the Filtered Back Projection (FBP) or the Maximum Likelihood

Expectation Maximization (MLEM) algorithms, follows naturally from the concept of Line Of Response

(LOR), and easily can account for the photon depth of interaction or annihilation photons time of flight

(TOF) information. The algorithm is carried out in two steps: first, a Butterworth filter is applied on the

reconstructed image to wipe out the low oversampled frequencies, and second, an adaptive median

filter is proposed as method to cancel the discontinuities produced by a fine pixilation of the image

space. Our algorithm has been evaluated with simulated and real data, and compared with some of

the gold-standard algorithms, such as FBP or List Mode Ordered Subset. In the case of the acquired

data, a Derenzo-like phantom was used showing the 1.6 mm rods, with a measured peak-to-valley of

2, in contrast to 1.25 and 1.23 for FBP and LMOS, respectively. In addition to the already mentioned

advantage, this algorithm provides the option of real time reconstruction.


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12:09 - 12:22 Strategies of Statistical Windows in PET Image Reconstruction to Improve the User's Real Time Experience L. Moliner1, C. Correcher2, V. Gimenez1, V. Ilisie1, S. Sanchez1, J. Alvarez1, M. J. Rodriguez1

1Institute for Instrumentation in Molecular imaging (i3M), Valencia, Spain 2Bruker Española, S.A, Spain.

Corresponding author: L Moliner, [email protected] Keywords: PET, Reconstruction algorithms, Image-guided interventions

Nowadays, with the increase of the computational power of modern computers together with

the state-of-the-art of reconstruction algorithms, it is possible to obtain PET images in practically real

time. These facts open the door to new applications such as the tracking of radio-pharmaceutics inside

the body or the use of PET for image-guided procedures, such as biopsy interventions, among others.

This work is a proof of concept that aims to improve the user experience with real time PET images.

Fixed, incremental, overlapping, sliding and hybrid windows are the different statistical

combinations of data blocks used to generate intermediate images in order to follow the path of the

activity in the Field Of View (FOV). To evaluate these different combinations, a point source is placed in

a dedicated breast PET device and moved along the FOV at different speeds. These acquisitions are

reconstructed according to the different statistical windows, resulting in a smooth transition of

positions for the image reconstructions that use the sliding and hybrid window.

Acknowledgements

This work was supported by the MAMMOCARE project (FP7-SME-2013-606017). Laura Moliner is

contracted by the Valencian Local Government under a VAL+ID grant.


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12:22 - 12:35 Cumulative Sums for Masking in Nuclear Medicine Image Reconstruction N. E. Protonotarios1,2 , G. M. Spyrou3,4, G. A. Kastis1

1Research Center of Mathematics, Academy of Athens, Greece 2Department of Mathematics, National Technical University of Athens, Greece 3Center of Systems Biology, Biomedical Research Foundation of the Academy of Athens, Greece 4Bioinformatics ERA Chair, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus

Corresponding Author: N E Protonotarios, [email protected] Keywords: Nuclear Medicine Image Reconstruction, Contour Detection, Image Masking, CUSUM

The issue of masking in nuclear medicine image reconstruction has been examined thoroughly in the

past, nevertheless most of the research has focused on the notion of either sinogram or image

segmentation. In this work we present an automated method for detecting the contour of objects in

emission tomography reconstructions, which can be used for image masking, attenuation correction,

as well as for eliminating streak artifacts outside the object being imaged. This was achieved by

applying cumulative sums (CUSUM) techniques on the sinogram. Our method can automatically detect

the object’s boundary in the reconstructed image. This masking approach has been tested in simulated

and real phantoms as well as real clinical studies, and it performed efficiently for all convex objects.

We were able to detect the boundaries of objects in the image space, which in turn enabled us to

eliminate streak artifacts outside, and thus to obtain image masks necessary for preliminary

attenuation correction.


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12:35 – 12:48 Improving PET Sensitivity with a Compton Algorithm V. Ilisie, L. Moliner, V. Gimenez, A. Aguilar, E. Lamprou, A. Gonzalez, F. Sanchez, J. M. Benlloch

Instituto de Instrumentación para Imagen Molecular (I3M), Centro Mixto CSIC - Universitat

Politècnica de València, Camino de Vera S/N, Spain

Corresponding Author: V Ilisie, [email protected]

Keywords: PET, Compton, Image Reconstruction

Current PET detectors have a very low sensitivity, of the order of a few percent. One of the reasons is

the that Compton events are being rejected. In this work we aim to prove that Compton events are a

very rich source of additional information that can play a crucial role in the image reconstruction

process. With this additional data, the detector sensitivity will be substantially improved and thus, the

applied dose on the patient can be reduced. This could be a really breaking point for PET detector

technology as one should be able to be able to obtain better image quality with less patient

radiation. By means of Compton cone matching (the Compton cones coming from the same event

should be compatible) one should be able do better recognize matching events and discard randoms

and even events that have previously suffered scattering within the patient’s body.

Acknowledgement

This work is supported by the European Research Council (ERC) under the Advanced Grant

695536 - 4D PET.


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12:48 – 13:01 Evaluation of the Spline Reconstruction Technique under the NEMA NU 4-2008 Standards A. Vrachliotis1, 4, G. A. Kastis2, 3, A. Gaitanis4, L. Costaridou1

1Department of Medical Physics, School of Medicine, University of Patras, Greece 2Research Center of Mathematics, Academy of Athens, Greece. 3Institute for Nuclear & Radiological Sciences & Technology, Energy & Safety, National Center for

Scientific Research “Demokritos”, Athens, Greece 4Biomedical Research Foundation, Academy of Athens (BRFAA), Greece.

Corresponding Author: A Gaitanis, [email protected]

Keywords: Image Reconstruction, micro-PET, SRT, NEMA NU 4-2008, STIR

The Spline Reconstruction Technique (SRT) is a new, fast algorithm based on a novel numerical

implementation of an analytic representation of the inverse Radon transform. The purpose of this

study is to simulate pre-clinical Positron Emission Tomography (PET) data and evaluate the

performance of SRT in comparison with Filtered Back Projection (FBP) and Ordered Subsets

Expectation Maximization (OSEM) under the NEMA NU 4-2008 standards. STIR software, was

employed to: (1) generate sinograms of the Image Quality (IQ) phantom and (2) reconstruct them with

SRT, 2D-FBP, 3D-FBP as well as OSEM for various combinations of subsets and iterations. ImageJ

software was employed to calculate image quality metrics such as: Uniformity, Recovery Coefficient

(RC) as well as Spill-Over Ratio (SOR). For the Uniformity measurements, SRT was comparable with 2D-

3D FBP as well as OSEM. The RC measurements revealed that SRT exhibited 3.3 - 17.5% improvement

over the other tested algorithms for the 2mm, 3mm, 4mm and 5mm rods, while results for the 1mm

rod were comparable. For the SOR measurements, SRT resolved both the water- and air- filled

cylindrical inserts, slightly better than 2D-3D FBP and OSEM. SRT appears to be particularly useful for

cold regions as well as small regions of interest (ROIs).

[email protected]

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13:01 – 13:14 Synthesis of Simultaneous Real Time Dynamic Positron Emission Tomography Data Using an Almost Continuous Respiratory Signal and Magnetic Resonance Imaging Data I. Polycarpou1, C. Tsoumpas2

1Department of Health Sciences, European University Cyprus, Cyprus 2Division of Biomedical Imaging, Leeds Institute for Cardiovascular and Metabolic Medicine, School

of Medicine, University of Leeds, UK

Corresponding Author: I Polycarpou, [email protected] Keywords: Computer simulation, Diagnostic medical imaging, Molecular imaging, Motion compensation, PET, Computational phantoms

Investigation of the performance of different reconstruction and motion compensation methods

requires an accurate representation of the anatomy and motion trajectories as observed in real

subjects during Positron Emission Tomography (PET). Generation of clinical datasets is difficult due to

the variable protocols, scanner specifications, patient variations. Alternatively, human-based

computational phantoms can be used to generate datasets. To incorporate motion into phantoms,

previous studies used dynamic image registration to derive voxel deformations and warp the

phantom. Furthermore, to simulate PET acquisition the phantoms are integrated in software tools. The

most commonly used method is based on Monte Carlo simulations which model the physical processes

accurately, but its high computational demands led to the use of faster methods. In this paper, a

method is proposed for synthesising PET data using a fast analytic method and incorporating motion

models into a numerical phantom to generate datasets with continuous and variable motion as

expected to be obtained during actual acquisitions. Real respiratory signals derived from PET were

combined with motion modelling derived from appropriate magnetic resonance imaging (MRI)

acquisitions. This approach allows incorporation of motion models to generate temporally and

spatially-correlated MRI and PET datasets, as expected to be obtained from simultaneous PET-MRI.

Acknowledgement

The authors would like to acknowledge Dr. Andrew King (King’s College London) and Dr. Paul Schleyer

(Siemens) for the contribution with motion modelling and respiratory signals.


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14:00 - 15:00 Session 3. Round table “Boosting Nanomedicine through the Efficient Application of Biomedical Engineering” Session Chairpersons: D. Glotsos, L. Fysikopoulos

14:00 - 14:15 Simulations for Magnetic Induced Hyperthermia K. Papadopoulos

Department of Medical Physics, Medical School, University of Patras, Greece

14:15 - 14:30 In Vivo Imaging During Magnetic Induced Hyperthermia L. Fysikopoulos

BET Solutions R&D Athens, Greece

14:30 - 14:45 Applications in Bone Regeneration P. Papadimitroulas

BET Solutions R&D Athens, Greece

14:45 - 15:00 Applications in Cardiology T. Kostou

Department of Medical Physics, Medical School, University of Patras, Greece

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15:30 - 17:00 Session 4. Safety and Quality in Health Care Session Chairpersons: B. Spyropoulos, M. Kallergi

15:30 - 15:45 Emerging Nano-technologies as reflected on recent and relevant industrial property documents B. Spyropoulos, E. Apostolatos, S. Kallivokas, P. Bakogiorgos, T. Politis, M. Neroupos, P. Papadaki,

D. Trichas

Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece

Corresponding Author: B Spyropoulos, [email protected] Keywords: Characterization of Nano-materials, Nanocrystal thin films, Microsensors, Photonic Crystals, Design, Atom Chips, Next Generation Photovoltaic, 3-D Nano Patterned Scaffolds for Cell -Culture Applications This paper resumes a new creative and innovative method of collective examinations of our

Biomedical Engineering (BME) graduate students; by assigning them an appropriate topic, they are

setting up a useful “mini-compendium” in a new and innovative area, in our case Nanotechnology, as

they are reflected upon published patent-applications. More specific the present “puzzle” consists of:

Analytical methods for characterization of Nanomaterials including size, shape, structure,

Chemistry, Crystallography etc.

Imaging methods as Electron microscopy, Ion microscopy, Atomic Force microscopy are, along

with elemental and structural analysis, through X-ray spectroscopy, Electron Spectroscopy and X-

Ray diffraction.

Nanocrystal line, bulk and thin film materials, Microsensors, sensored Microsystems and Atom-

chips.

Next Generation organic Photovoltaic clusters, powering low-consumption devices are described.

Finally, 3-d nano-patterned Scaffolds for Cell Culture Applications are concluding this approach to

emerging nanotechnologies, especially relevant for Biomedical Engineering graduate-students.

This method is successfully employed for 10 years in our ICT and BME Graduate Courses and allows for

training of our students in “traditional” scientific literature search and deepening in important aspects

of an emerging new and innovative subject, by taking advantage of being acquainted with the taught

methodology of Industrial Property Rights searches that are almost neglected in most Greek

Universities.


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15:45 - 16:00 Emerging Radiotherapy Technologies: Facilities Equipment, Safety and Innovation B. Spyropoulos, E. Apostolatos, S. Kallivokas, P. Bakogiorgos, T. Politis, M. Neroupos, P. Papadaki,

D. Trichas


Corresponding Author: B Spyropoulos, [email protected] Keywords: RT-Facility implementation, RT staffing, External RT beam therapy, LDR MDR & HDR Brachytherapy, Equipment for external beam RT & Brachytherapy, RT Physical & Clinical Aspects of Quality Assurance, Maintenance & Safety Programme

This paper resumes Facilities, Equipment, Safety and Innovation serving modern Radiotherapy, by

linking Clinical–Technical Regulations, to post-treatment Home-care. A group of seven Biomedical

Engineering (BME) graduate students, worked on this collective interdisciplinary final examination

project, for their 4th trimester of this Course. More specific the present modular project consists of:

Programme implementation: Staff training, Equipment specification, Planning and construction of

Facilities, Delivery of equipment, Planning and initiation of treatment, Patient throughput

assessment Follow-up and assessment mission, Radiation safety.

External RT beam therapy: Examination rooms, Simulator/CT/MRI, Treatment planning room,

Mould room, Treatment room, waiting areas.

Low, medium and high dose rate Brachytherapy: Sources storage and preparation room,

Operating theatre, Treatment planning room, Patient rooms, Imaging equipment, Proper

Implants, Equipment for treatment planning, Treatment delivery equipment, Quality assurance

equipment, Equipment for radiation safety and source handling.

Clinical aspects of quality assurance programme: Treatment policies, Clinical case conferences for

review of proposed/recent patient treatments, Clinical follow-up and statistical review.

Physical aspects of quality assurance programme: Radiotherapy planning and delivery, Initial

evaluation, Therapeutic decisions for external beam radiotherapy and Brachytherapy.

Maintenance programme and medical-managerial measures: Preventive maintenance, Repairs,

Spare parts, Accidental medical exposures, Quality audits management, Personnel continuous

training.

This approach is successfully employed for 10 years in our ICT and BME Graduate-Courses.


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16:00 - 16:15 Applications and Impact of 5G and IoT on Health Services by the year 2025 as predicted on Relevant Patent-Documents M. Bania1, B. Spyropoulos1, 2

1Graduate Program “Information Technologies in Medicine and Biology”, Department of Informatics

and Telecommunications, National and Kapodistrian University of Athens, Greece 2Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece

Corresponding Author: B Spyropoulos, [email protected] Keywords: Fifth-generation wireless mobile-network technology (5G), Internet of Things (IoT), Health-

Care, Hospital, Home-care, Patents, Industrial Property Documents

The aim of this paper is to outline the disrupting fifth-generation wireless mobile-network technology

(5G) and the way it will gradually affect the Health-services, supported and automated by the Internet

of Things (IoT). Future 5G networks will be about 100 times faster, non-loss of communication should

be their central feature and their major-goal, beyond the dramatically enhanced interconnection of

people, is the interoperable and automated interlacing of any devices, within the same network.

Undoubtedly, 5G technology will upgrade Health-care services, both, in Hospital and in Home-care.

The Hospital includes five major areas that will be directly affected:

The Emergency and Outpatient Departments.

The Imaging and Radiotherapy Departments.

The Surgical Departments, the Intensive Care Units (ICU/CCU, NICU etc.) and the Wards.

The in vitro Diagnostics, Hematology, Transfusion Medicine, Cell Therapy Laboratories and Units.

The various Supporting Facilities (e.g. Sterilization, Laundry, Personnel and Patients Food-services,

E/M Engineering Facilities, Warehouse etc.).

Home-care and Health self-inspection will be increasingly employed for caring about major social

groups, as the ageing population and people physically and/or mentally impaired. Methodologically,

this task is being accomplished, by monitoring and evaluating the relevant to the subject-matter

recent Publications and published Industrial Property Documents, predicting the 8 years to come.


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16:15 - 16:30 Quality Assurance in Point of Care Arterial Blood Gases Measurements K. Lydakis, B. Spyropoulos

Department of Biomedical Engineering, Technological Education Institute of Athens, Greece

Corresponding Author: B Spyropoulos, [email protected] Keywords: Arterial Blood Gases, Acid-Base balance, ABG-analyzer, ISO 15189:2012, ISO 22870:2016

Arterial Blood Gases (ABG) measurements are often used in Clinical practice, in order to determine the

Oxygenation and the level of a patient’s Acid-Base balance; they are particularly important in cases

such as:

Respiratory control of cardio-pulmonary diseases.

Precise determination of O2 level of a patient.

Acid-Base balance assessment.

Monitoring of treatment in general, in cases of heart failure, serious infections, after

administrating suppressive medication, checking drug-addicted persons etc.

The purpose of this project was to carry-out daily, monthly and annual inspections and maintenance of

Blood Gas Analyzers, as specified in the Radiometer-ABL555 Service Manual. All relevant parameters

(pH, PCO2, tCO2, PO2, K+, Na+, Lac, Ca++, Cl-, Glu) of the ABG-equipment, of the Venizeleion General

Hospital of Heraklion, should be kept within the permitted limits. A data-base was created, comprising

of recordings for 50 days:

Daily measurements on the five Radiometer-ABL555 analyzers.

Daily equipment Calibration and Quality-control data for all parameters.

Anonymized recordings of all patients’ Blood-gas measurements based on gender, age and ICD-10

Diagnostic-codes.

The corresponding Levey-Jenings charts for all ABG-equipment and parameters.

The full-data collected from the ED/ICU/CCU/NICU and Cardiology/Pulmonary Clinics, constitute the

road-map for a permanent effective ABG-PoCT Quality Assurance Programme.


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16:30 - 16:45 ICT-Driven Smart Green Hospitals: Reducing Superfluous Cost B. Spyropoulos1, 2, Α. Alexandropoulos2, N. Boci2, E. Chatziapostolou2, E. Frappa2, E. Georgiadou2, I.

Louts2, I. Pantelakis2, M. Poultsaki2, M. Xenaki2

1Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece 2Graduate Program “Information Technologies in Medicine and Biology”, Department of Informatics

and Telecommunications, National and Kapodistrian University of Athens, Greece

Corresponding Author: B Spyropoulos, [email protected] Keywords: Mobile IP-networks, Service-oriented architecture, Ubiquitous-computing, Femtocells, Wireless mesh-networks, Multimedia-sharing, Green-computing, 5G, Internet of Things (IoT), Health-care, Hospital, Home-care, Industrial Property Documents

The Hospital is the most complex and representative establishment of the society, and nowadays, the

most costly one. ICTs may rationalize personnel-efforts and reduce energy and material-wasting, to

enable health-care coverage, of unprivileged social-groups. The aim of the paper is to present the most

effective and efficient means and tools, reducing unnecessary cost, as:

Mobile IP-networks: IETF-standard communications-protocol allowing mobile-device users to

move from one network to another, maintaining a permanent IP address.

Service-oriented architecture, provided to other components by application-components, through

a communication protocol, over a network.

Ubiquitous-computing appears anytime and everywhere, by embedding microprocessors into

objects, allowing communication and task-performing.

Femtocells, small, low-power cellular base-stations, typically designed for use in a hospital-

department, ward-room or unit.

Wireless mesh-networks, made-up of radio-nodes, organized in a mesh-topology, supporting

intra-hospital data-exchange.

Multimedia-sharing over wireless networks for real-time or compressed (PACS, ICU, Lab etc.) data-

streaming over IP/wireless-networks for communication or archiving.

Green-computing in wireless-networks mobile cloud-computing, limiting useless people and

material intra-hospital “circulation”, enabling environmentally friendly and smooth procedures.

Standardization, policy and regulation for green communications and computing.

Communication Technologies for “green” buildings.

ICTs enable procedures-optimization, solving energy- and material-waste problems, reducing the

overall operational-cost, in the emerging “green networked” Hospital, in favor of the people in need.


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16:45 - 17:00 The Smart Hospital Room: Discerning among Myth and Reality B. Spyropoulos


Corresponding Author: B Spyropoulos, [email protected] Keywords: Medical Records, Cognitive-computing, Patient-participation, Real-time access, Overloaded Clinical staff, Goal-oriented training, Patient care-plan, Patents

Numerous solutions have been proposed for the future “Smart Hospital-Room”, however, there is little

progress made. Interesting approaches include the Amplion Smart(er) Room of the Future, the IBM-

UPMC (University of Pittsburgh Medical-Center), the NXT-Health-program of the US-Department of

Defense and the EU-Agency for Network and Information Security. Nevertheless, a Hospital Smart-

Room has to be cost-effective and it is the aim of this project, to pinpoint the most important catches.

Crucial delay-factors and high-cost sources have been traced, by following the innovation trail, as

reflected upon numerous Hospital-Technology related Publications and Patents, synopsizing:

The obstacles for achieving an acceptable and interoperable Electronic Medical Record.

Enhanced cognitive-computing based ways to harness, share, manage and trace big-data.

Why increased patient-interactivity and participation, is a cardinal challenge for future’s Smart-

Room.

That Health-care providers need access to real-time, point-of-care feedback, on a continuous

basis.

That Technology supporting overloaded clinical-staff causes sometimes complications and

tensions.

Why clinical-workflow improvements, require goal-oriented training, on patient-care-plans,

supported by mature and cost-effective technologies.

Cost, lack of education and short-term focusing lead to cul-de-sac. The hospital-leaders must realize

that the world is changing dramatically; in order to survive, they have to offer smart, innovative,

efficient and cost-effective Health-care-solutions.


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17:30 - 18:30 Session 5. Round table “Radiation Protection: New BSS Directive and Current Trends” Session Chairpersons: E. P. Efstathopoulos, G. S Panayiotakis

The Implication of DRLs using the New Directive. A Case Report from University Hospital of Patras G. A. T. Messaris1, G. S. Panayiotakis1, 2

1Department of Medical Physics, University Hospital of Patras, Greece 2Department of Medical Physics, School of Medicine, University of Patras, Greece

Corresponding author: G Panayiotakis, [email protected] Keywords: Diagnostic Reference Levels, Patient Radiation Dose

The concept of Diagnostic Reference Levels (DRLs) was initially introduced in 1997 in Europe by the

Directive 97/43/EURATOM. At that time the DRLs were defined as dose levels in medical radio-

diagnostic practices to patients of standard-sized groups or standard phantoms, for typical and

broadly defined types of examinations. This directive was recently replaced (2013) by the Directive

2013/59/EURATOM, which emphasizes the importance and extends the definition of DRLs and has to

be adopted by all member states until 6/2/2018. Taking into account this obligation from the Greek

legislation, in combination with the existence of national DRLs for numerous x-ray examinations,

Institutional Dose Levels (IDLs) for indicative examinations, at the Department of Radiology of the

University Hospital of Patras, are presented. Complementary to this, issues regarding the collection

methodology and processing of data, for the extraction of IDLs are outlined, using the framework of

dosimetry services described in the current directive.


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Overview of the 2013/59 Euratom Basic Safety Standards Directive

-Radiation Protection of Workers K. Platoni

2nd Department of Radiology, University General Hospital “Attikon”, School of Medicine,

National and Kapodistrian University of Athens, Greece

-Radiation Protection of Patients S. Triantopoulou

Athens General Children's Hospital “Pan. & Aglaia Kyriakou”, Athens, Greece

-Equipment Requirements I. Stathopoulos

2nd Department of Radiology, University General Hospital “Attikon”, School of Medicine,

National and Kapodistrian University of Athens, Greece

Corresponding author: K Platoni, [email protected] Keywords: European Directive, Basic Safety Standards, radiation protection

The technological advances, the new recommendations of the ICRP and the increased frequency of

examinations involving exposure to ionizing radiation led to the promulgation of the new 2013/59

Euratom Directive.

The new Directive laying down basic safety standards for protection against the dangers arising from

exposure to ionizing radiation, provides new definitions and new dose limit for eye lens, emphasizes

the need for justification, optimization and education and highlights the role of medical physics expert,

Moreover, it is of particularly interest that the revised Directive introduces new equipment

requirements concerning radiation dose monitoring and recording. The Member States of the

European Union must comply with the new Directive by 6 February 2018.

The aim of the current study is to describe the fundamental aspects of the new Directive and to

highlight the main differences and changes in comparison to the previous existing Directives,

regarding: i) radiation protection of workers, ii) radiation protection of patients and iii) equipment

requirements.


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The impact of Radiation Protection Culture

A. Ploussi

2nd Department of Radiology, University General Hospital “Attikon”, School of Medicine, National

and Kapodistrian University of Athens, Greece

Corresponding Author: A Ploussi, [email protected] Keywords: Radiation Protection Culture, Radiology Department

The increase in medical radiation exposure in recent years necessitates the establishment of Radiation

Protection Culture (RPC). RPC is a newly introduced meaning that describes the combination of

knowledge, practices and behaviors among professionals, staff and patients concerning radiation

protection aspects.

The main objectives of RPC are to promote knowledge of radiation risks, minimize unsafe practices and

provide a safe working environment. The establishment of RPC requires continuous education and

training, active stakeholder engagement as well as quality assurance programs. Professionals and

staff have a key role in the implementation of RPC. A strong RPC enables the reduction of radiation

dose on both patients and staff, provides more efficient diagnosis and treatment and improves the

service quality of a Radiology Department

The aim of the current study is to provide the ways for establishing RPC and highlight the role and the

impact of RPC in a Radiology Department.


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Parallel Poster Session-A (10:30– 18:30) Session Chairpersons: S. Kostopoulos, C. Michail

Thursday 12, October 2017 (24 Posters)

1. 3D Printing X-ray Quality Control Phantoms. A Low Contrast Paradigm I. Kapetanakis, G. Fountos, C. Michail, I. Valais, N. Kalyvas

Department of Biomedical Engineering, Technological Educational Institute Egaleo Greece

Corresponding Author: N Kalyvas, [email protected] Keywords: 3d printer, low contrast, Phantom Current 3d printing technology products may be usable in various biomedical applications. Such an

application is the creation of X-ray quality control phantoms. In this work a self-assembled 3d printer

(geeetech i3) was used for the design of a simple low contrast phantom. The printing material was PLA

(100% printing density). Low contrast scheme was achieved by creating air-holes with different

diameters and thicknesses, ranging from 1mm to 9mm. The phantom was irradiated at a Philips

Diagnost 93 fluoroscopic installation at 40kV-70kV with the semi-automatic mode. The images were

recorded with an Agfa cr30-x CR system and assessed with ImageJ software. The best contrast value

observed was approximately 33%. In low contrast detectability check it was found that the 1mm

diameter hole was always visible, for thickness larger or equal to 4mm. A reason for not being able to

distinguish 1mm in smaller thicknesses might be the presence of printing patterns on the final image,

which increased the structure noise. In conclusion the construction of a contrast resolution phantom

with a 3d printer is feasible. The quality of the final product depends upon the printer accuracy and the

material characteristics.

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2. 3D Tomographic Imaging with the γ-Eye Planar Scintigraphic Gamma Camera H. Tunnicliffe1 ,2, M. Georgiou3, G. Loudos4, 5, A. Simcox1, 2, C. Tsoumpas2

1School of Physics and Astronomy, University of Leeds, UK 2Division of Biomedical Imaging, Institute of Cardiovascular and Metabolic Medicine, University of

Leeds, UK 3BET Solutions, Research & Development, Athens, Greece 4Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece 5National Centre for Scientific Research NCSR “Demokritos”, Institute of Nuclear and Radiological

Sciences and Technology, Energy and Safety, Athens, Greece

Corresponding Author: C Tsoumpas, [email protected] Keywords: Single Photon Emission Computed Tomography, Small Animal Imaging, QSPECT, STIR

The γ-eye camera is a desktop planar scintigraphic gamma camera with a 100x50mm field of view,

designed by BET solutions to be an affordable tool for whole body, small-animal imaging. An

investigation has been made into the viability of using the γ-eye system for the collection of

tomographic data for 3D SPECT reconstruction.

Two software packages, QSPECT and STIR (Software for Tomographic Image Reconstruction), have

been investigated. Reconstructions have been performed using QSPECT’s implementation of the OSEM

algorithm and STIR software package’s OSMAPOSL (Ordered Subset Maximum A Posteriori One Step

Late) algorithm. Also, STIR’s implementation of the OSSPS (Ordered Subsets Separable Paraboloidal

Surrogate algorithm) algorithm was investigated briefly. Reconstructed images of phantom and

mouse data have been assessed in terms of spatial resolution, sensitivity to varying activity levels and

uniformity. The effect of varying the number of iterations, the voxel size (1.25 mm default voxel size

reduced to 0.625 mm and 0.3125 mm), the point spread function correction and the weight of prior

terms were explored.

While QSPECT demonstrated much faster reconstruction times, STIR outperformed it in terms of

resolution (as low as 1 mm), particularly when smaller voxel sizes were used and in terms of

uniformity, when prior terms were used. However, both were at the cost of further increases in

reconstruction time. Little difference in terms of sensitivity was seen throughout.

Overall it has been demonstrated that the γ-eye camera can be used to produce 3D tomographic

images of sufficient quality for small animal imaging, with STIR generally offering the best

performance.


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3. A Digital Data Acquisition Scheme for SPECT and PET Small Animal Imaging Detectors for Theranostic Applications M. Georgiou, E. Fysikopoulos, G. Loudos

Department of Biomedical Engineering, Technological Educational Institution of Athens, Greece

Corresponding Author: M Georgiou, [email protected] Keywords: SPECT, PET, Silicon Photomultiplier (SiPM), Data Acquisition System (DAQ), Field Programmable Gate Array (FPGA), Hyperthermia

Nanoparticle based drug delivery is considered as a new, promising technology for the efficient

treatment of various diseases. When nanoparticles are radiolabelled it is possible to image them, using

molecular imaging SPECT or PET techniques. The use of magnetic nanoparticles in hyperthermia is one

of the most promising nanomedicine directions and requires the optimization of magnetic induction

devices, as well as the accurate, non-invasive, monitoring of temperature increase and drug release.

The combination of imaging and therapy has opened the very promising Theranostics domain.

Moreover, the introduction of MR compatible Silicon Photomultipliers (SiPMs) exploded the interest in

hybrid PET/MR and SPECT/MR research.

We present a digital data acquisition scheme for SPECT and PET small animal imaging detectors for

Theranostic applications. Two embedded systems were developed using a single reprogrammable

acquisition platform (FPGA LX150T Development board) in order to acquire digitized data from the

detectors. A digital version of the constant fraction discriminator (CFD) method was implemented for

the generation of the event timestamp for the PET detector. The information of interest (position and

energy for SPECT along with timing for PET), computed inside the FPGA, is written to an external

memory and transferred to a PC, via Ethernet link, for image reconstruction.

Acknowledgement

"This research is implemented through IKY scholarships programme and co-financed by the European




Reference Framework (NSRF) 2014 – 2020."


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4. A Mathematical Model for Texture Simulation in Microscopy D. Glotsos1, S. Kostopoulos1, P. Ravazoula2, C. Stefanoudakis1, P. Bavela1, D. Cavouras1

1Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece 2Department of Pathology, University Hospital of Patras, Greece

Corresponding Author: D Glotsos, [email protected] Keywords: Microscopy, Synthetic Nuclei Images, Image Quilting

The aim of this study is to propose a mathematical model based on image quilting for creation of

synthetic nuclei images that may be used for evaluating the performance of nuclei detection

algorithms. Clinical data comprised 50 biopsy samples obtained from tumors of the central nervous

system. The histological material was processed with the Haematoxylin and Eosin staining protocol,

which enhances the contrast of nuclei regions. From each samples, images were digitized using a Leica

DM2500 microscope coupled to a DFC420 CCD digital camera at 40x magnification. Samples from

nuclei and surrounding background regions were manually obtained from digitized images. These

samples were used as input to an image quilting algorithm that produced two distinct images, one for

simulating the texture of nuclei regions and another for simulating the texture of surrounding tissue

regions. The final synthetic image was produced by combing the nuclei and surrounding tissue images

using an image registration approach with wavelets. Results showed that synthetic images were

similar to real images according to experts’ visual evaluation. The synthetic images may be used to

optimize the performance of nuclei detection algorithms, since they provide a gold standard reference.

Acknowledgement

This research is funded by the “Special Account for Research Grants” of the TEI of Athens, in the

framework of the Internal Programme for the Support of the TEI of Athens Researchers, for 2015.


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5. A Pilot Database of Biomedical Engineering Companies A. Ilias, D. Glotsos


Corresponding Author: D Glotsos, [email protected] Keywords: Biotech Industry, Biomedical Engineering, Biotechnology Companies

Biomedical engineering is currently considered as the fastest growing sector in terms of occupation

according to the U.S. Bureau of Labor Statistics, with an estimate of 62% increase in job openings in

the next few years. The aim of this study was to develop a pilot online database of Biotech companies

to be used as a tool for mapping the current activity, trends and future perspectives of the Biotech

industry in Greece and other major European countries. The database is an ongoing project that

currently comprises 311 listings in Greece, 88 in Italy, 65 in UK, 169 in Germany, 84 in Spain, 52 in the

Nederland’s, 83 in Denmark and 14 in Cyprus. Each listing contains information regarding the name of

the company, location, contact details, website address and fields of activity (i.e. manufacturing,

research, services, sales, support, in vitro, in vivo, equipment, medical imaging, quality control,

medical electronics etc). The database was implemented into two different open source platforms,

google drive and wordpress. The google drive edition enables search and sorting of the entries

according the criteria such as location and activity. The wordpress edition incorporates a search

engine and a google map functionality with pined the location of each listed Biotech company. Both

platforms may be accessed at http://www.bmeonline.eu/. The proposed database may be used for

investigating the future perspectives of the worldwide rapidly growing Biotech industry that supports

the two major pillars of the modern health care sector, the improvement of health quality and the

support of the ageing population.


http://www.bmeonline.eu/

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6. A Real Time ECG Signal Processing Application for Arrhythmia Detection on Portable Devices A. Georganis1, N. Doulgeraki1, P. Asvestas2

1Department of Informatics and Telecommunications, National and Kapodistrian University of Athens, Greece 2Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece

Corresponding Author: A Georganis, [email protected] Keywords: Arrhythmia, ECG features, Android, Classification


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7. ABC Triblocks as Nanocarriers for Curcumin A. Skandalis, S. Pispas

Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens, Greece

Corresponding Author: A Skandalis, [email protected] Keywords: Triblock, Terpolymer, Amphiphilic, Nanocarriers, Curcumin Amphiphilic block copolymers self-assemble in organized nanostructures such as micelles or vesicles

when inserted in water. This property has made them a hot topic in the worldwide scientific

community. Here, we synthesized novel amphiphilic triblock terpolymers of PDMAEMA-b-PLMA-b-

POEGMA by RAFT polymerization methodologies. The terpolymers were molecularly characterized by

size exclusion chromatography (SEC) and proton nuclear magnetic resonance spectroscopy (1H-NMR).

The terpolymers form spherical micelles in aqueous solutions, with a PLMA hydrophobic core and a

mixed PDMAEMA/POEGMA hydrophilic corona. Critical micelle concentrations (CMCs) were

determined to be very low by fluorescence spectroscopy (FS). The polymeric micelles were utilized as

nanocarriers for the encapsulation of the model drug curcumin. Interactions of the terpolymers with

curcumin were studied by FT-IR spectroscopy. The encapsulation efficiency of the terpolymers was

determined by UV experiments. Stable micelles encapsulating a curcumin amount equal to the PLMA

content were formed. . Static, dynamic and electrophoretic light scattering (SLS, DLS, ELS) were used

for determining the mass, size, morphology and surface charge of PDMAEMA-b-PLMA-b-POEGMA

block copolymers micelles, as well as the micelles encapsulating-curcumin. All systems were found to

be in the nanoscale range allowing for their utilization in drug delivery.

Acknowledgement

Financial support to this work by the Greek State Scholarships Foundation through the program

“Enhancement of human scientific resources though implementation of PhD research” with resources

of the European program “Development of human resources, Education and lifelong learning”, 2014-

2020, co funded by the European Social Fund and the Greek State, is greatfully acknowledged.


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8. Antepartum Fetal Monitoring and Spectral Analysis of Preterm Birth Risk A. Pasarica1, D.Nemescu2, D. Arotaritei3, C. Rotariu3

1Department of Telecommunications, “Gheorghe Asachi” Technical University of Iasi, Romania 2Department of Obstetrics and Gynecology, “Grigore T. Popa” University of Medicine and Pharmacy,

Romania 2Department of Biomedical Sciences, “Grigore T. Popa” University of Medicine and Pharmacy,

Romania

Corresponding Author: C Rotariu, [email protected] Keywords: Fetal monitoring, Heart rate, Spectral analysis, Preterm birth risk The monitoring and analysis of antepartum fetal and maternal recordings is a research area of notable

interest due to the relatively high value of preterm birth. The interest stems from the improvement of

devices used for monitoring. The current paper presents the spectral analysis of antepartum heart rate

recordings conducted during a study in Romania at the Cuza Voda Obstetrics and Gynecology Clinical

Hospital from Iasi between 2010 and 2014. The study focuses on normal and preterm birth risk

subjects in order to determine differences between the two types or recordings in terms of spectral

analysis.

Preterm birth risk is an issue of interest for health care professionals given the most recent European

statistics presented in the European Perinatal Health Report 2010, which show rates between 5 and

10% for all European countries, and 8% for Romania.

The results presented in this paper represent the spectral analysis of antepartum recordings of fetal

and maternal heart rate (FHR and MHR) during the third trimester of pregnancy. The purpose is to

show the efficiency of this type of clinical practice as a complimentary procedure to standard testing

such as echography during key stages of pregnancy and close observation from health care specialists.

Acknowledgement

This work was supported by the project "Remote Monitoring of Physiological Parameters to Improve

the Prediction of Fetal Outcome", financed by the "Grigore T. Popa" University of Medicine and

Pharmacy, Iasi, Romania, contract 31592/23.12.2015.


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9. Artifacts Quantification of Metal Implants in MRI I. Vrachnis1, G. Vlachopoulos1, T. Marris2, L. Costaridou1

1Department of Medical Physics, School of Medicine, University of Patras, Greece 2Department of Medical Physics, Faculty of Medicine, University of Crete, Iraklion, Greece

Corresponding Author: G Vlachopoulos, [email protected] Keywords: MRI, Metal Implants, Artifacts, Quantification

The presence of materials with different magnetic properties, such as metal implants, causes

distortion of the magnetic field locally, resulting in susceptibility artifacts. Quantitive and unbiased

measurement of the artifact is prerequisite for optimization of acquisition parameters. In our study we

propose a fully algorithmic method for susceptibility artifact quantification.

Susceptibility artifact results in signal voids or pill up, which are translated in abrupt signal alteration

and consequently at high image gradient. According to the proposed method image gradient

magnitude is calculated after a denoising step and then an automatic cross entropy thresholding

method is applied. Artifact is quantified as image area percentage at the resulting binary image.

The propose method, gives moderate to good correlation, when compared with the method proposed

by Kolind S et al, which was used as a reference method

The propose method was scheduled for artifact quantification in phantoms containing two materials

with greatly varying magnetic permeabilities. Being fully algorithmic is objective and repeatable and

thus suitable for acquisition parameters optimization.


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10. Biocompatible Polyoxazoline Polymers as Gene Vectors E. Vlassi, A. Papagiannopoulos, S. Pispas


Corresponding Author: E Vlassi, [email protected] Keywords: Poly(2-oxazoline)s, DNA, Complexes, Gene delivery, Light scattering

Poly(2-oxazoline)s are referred as smart bioinspired polymers due to their structural similarity with

polypeptides. Especially, poly(2-phenyl-2-oxazoline) (PPhOx) has a hydrophobic character and its

monomeric unit structure is isomeric to phenylalanine. On the other hand, the cationic polymer

poly(ethylene imine) (PEI) has been widely used for non- viral transfection in vitro and in vivo

combining strong DNA compaction capacity with a intrinsic endosomolytic activity. In this work,

PPhOx-co-PEI amphiphilic random copolymers were prepared by partial acidic hydrolysis of poly(2-

phenyl-2-oxazoline) from cationic polymerization. Their molecular characteristics are determined by

size exclusion chromatography (SEC), proton nuclear magnetic resonance (1H NMR) and Fourier

Transform infrared spectroscopy (FTIR). The self-organized PPhOx-co-PEI behavior in aqueous solutions

was elucidated by light scattering (DLS, SLS) and zeta potential measurements. In order to investigate

the impact of PPhOx-co-PEI on the particle size, we measured the hydrodynamic diameters not only at

different concentrations in water, but also in different salt concentrations. The PPhOx-co-PEI

copolymers form polyplexes with DNA. While DNA concentration in the aqueous solution was

increased, the polyplex size was decreased giving better-defined nanoparticles, and showing the

compaction ability of the novel amphiphilic copolymers.


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11. Block Copolymers with Regulated Amphiphilicity as Nanocarriers for Gene Delivery M. Kafetzi, S. Pispas


Corresponding Author: M Kafetzi, [email protected] Keywords: Gene delivery, Amphiphilic block copolymers, pH-sensitive block copolymers, Temperature-stimuli block copolymers, Polyplexes Amphiphilic block copolymers containing a cationic block, present the ability to form polyplexes with

DNA and RNA. As a result, they function as nanocarriers for gene delivery. Amphiphilic block

copolymers have been used extensively for these purposes because of their ability to self-assemble into

nanoparticles when inserted in water. pH-responsive and temperature responsive block copolymers,

can change their conformation and supramolecular aggregation state in response to pH and

temperature changes, respectively. These characteristics led to modified morphologies, controlled

particles size and allowed for utilization in biomedical applications. Here, we synthesized the novel

poly[(2-(dimethylamino)ethyl methacrylate-co-(lauryl methacrylate)]-block-poly[oligo(ethylene

glycol)methyl ether methacrylate)] block copolymers via Reversible Addition-Fragmentation chain

Transfer polymerization (RAFT) and they were examined towards utilization as DNA carriers.The

properties of the polyplexes in aqueous solutions have been investigated by Dynamic, Static and

Electrophoretic Light Scattering (DLS, SLS, ELS), Fluorescence spectroscopy (PS) and Ultraviolet-Visible

Spectroscopy (Uv-Vis). The study of the polyplexes have shown that the size of the polyplexes depends

on the charge ratio between DNA and cationic block of the copolymer. Specifically, increasing the N/P

ratio leads to a size increase. Moreover, the surface charge values decrease as the N/P ratio increases.

Finally, it was observed that these complexes present great stability over time.

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12. Body Mass Index and Patient Dose in Fluoroscopically Guided Lumbar Discectomy and Fusion V. Metaxas1, G. Messaris1, G. Gatzounis2, F. Tzortzidis2, D. Konstantinou2, G. Panayiotakis1

1Department of Medical Physics, School of Medicine, University of Patras, Greece 2Department of Neurosurgery, School of Medicine, University of Patras, Greece

Corresponding Author: G Panayiotakis, [email protected] Keywords: Lumbar discectomy and fusion, Fluoroscopy, Patient dose, Body mass index

A survey was conducted to evaluate radiation dose with regard to the patients’ body size during

lumbar discectomy and fusion. Fluoroscopy time (FT), kerma area product (KAP), cumulative dose (CD),

as well as anatomical and technical data were registered for 100 patients operated by three

neurosurgeons, utilizing a C-arm fluoroscopy system (Philips BV Endura). The patients were

categorized in three groups based on body mass index (BMI) values: normal, overweight, and obese.

Entrance surface dose (ESD), effective dose (ED) and gonadal dose were estimated, utilizing

appropriate conversion coefficients. The mean FT, KAP, CD, ESD, ED and gonadal dose values were

13.2 s, 0.74 Gy·cm2, 3.35 mGy, 11.2 mGy, 0.09 mSv and 0.03 mGy for normal, 21.2 s, 0.90 Gy·cm2, 4.1

mGy, 18.0 mGy, 0.11 mSv and 0.03 mGy for overweight, and 52.6 s, 2.80 Gy·cm2, 13.9 mGy, 44.7 mGy,

0.34 mSv and 0.16 mGy for obese patients, respectively. BMI had a significant influence on patient

dose. Overweight patients received 61% and 22%, while obese patients 300% and 280% higher ESD

and ED compared to normal patients, respectively. A careful adjustment of exposure protocols is

required to balance between patient dose and image quality, with respect to the patient’s size;

however, further studies should be performed towards the optimization procedure.


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13. Breast Radiation Dose in Digital Mammography A. Lekatou1, G. Messaris1, V. Metaxas1, P. Antzele2, G. Tzavellas2, G. Panayiotakis1

1Department of Medical Physics, School of Medicine, University of Patras, Greece 2Department of Radiology, University Hospital of Patras, Greece

Corresponding author: G Panayiotakis, [email protected] Keywords: Digital Mammography, Breast Dose

Breast dose surveys in screening mammography constitute valuable tools towards patient’s radiation

protection. In this study, breast dose data in digital mammography examinations conducted at the

University Hospital of Patras, are presented and compared with corresponding values already

published. Three hundred and ten women, 40-80y, participated in the study. All mammographic

examinations were performed with a Hologic Selenia Dimensions digital mammography unit. The

patient characteristics, exposure and technical parameters (tube voltage, tube load, target/filter

material, compressed breast thickness (CBT)), entrance surface dose (ESD) and average glandular dose

(AGD) were recorded. The breast doses were estimated for projections, craniocaudal (CC) and oblique

(MLO). Additionally, the corresponding 75th percentile values, for CBT 55-65mm, were estimated for

comparison purposes. The mean AGD and ESD values for both projections were 1.33mGy and

5.43mGy, respectively. The 75th percentile values for AGD and ESD distributions were 1.44mGy and

6.01mGy for projections, 1.41mGy and 5.79mGy for CC and 1.48mGy and 6.17mGy for MLO,

respectively. The estimated values for CC projections were 8.4% and 17.3% lower than the national

diagnostic reference levels, while the values of AGD for all projections were 42% lower than the

corresponding European values. The institutional doses reported could contribute in the establishment

of local DRLs and in the effort for further radiation protection in mammography.

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14. Computational Study of the Optimum Gradient Magnetic Field for the Navigation of Spherical Particles into Targeted Areas E. G. Karvelas1, 2, N. K. Lampropoulos1, D. I. Papadimitriou1, I. E. Sarris1

1Department of Energy Technology, Technological & Educational Institute of Athens, Greece 2Department of Civil Engineering, University of Thessaly, Volos, Greece

Corresponding Author: E G Karvelas, [email protected] Keywords: Magnetic driving, Nanoparticles, CFD, MRI

The use of spherical magnetic nanoparticles that are coated with drugs and can be navigated to

targeted areas, is proposed for the cure of cancer. The particles are navigated by magnetic field

gradients that can be produced by an MRI device. In the present work, a computational study for the

estimation of the time evolution of the gradient magnetic field is presented in order to ensure the

optimum driving of the particles into the targeted area. For this purpose, the presented method

includes all the forces that act on the particles and make them move. The method is based on an

iteration algorithm that intends to minimize the deviation of the particles from a desired trajectory. In

this way, the gradient magnetic field is temporarily adjusted in a suitable way such that the particles’

distance from the trajectory to be decreased. For the evaluation of the potentials of this

computational method, series of simulations with different numbers of optimization parameters for

the magnetic field, fluid velocities, and geometries were performed. Using the above mentioned

method, it was depicted that this method can navigate the magnetic particles into the desired area.


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15. Design and Implementation of a Brain Computer Interface System for Controlling a Robotic Claw

D. Angelakis1, S. Zoumis1, P.Asvestas1


Corresponding Author: D Angelakis, [email protected] Keywords: Brain, Electroencephalogram, BCI, Arduino, Emotiv Epoc, Robotic claw The aim of this paper is to present the design and implementation of a brain-computer interface (BCI)

system that can control a robotic claw. The system is based on the Emotiv Epoc headset, which

provides the capability of simultaneous recording of 14 EEG channels, as well as wireless connectivity

by means of the Bluetooth protocol. The system is initially trained to decode what user thinks to

properly formatted data. The headset communicates with a personal computer, which runs a

dedicated software application, implemented under the Processing integrated development

environment. The application acquires the data from the headset and invokes suitable commands to

an Arduino Uno board. The board decodes the received commands and produces corresponding

signals to a servo motor that controls the position of the robotic claw. The system was tested

successfully on a healthy, male subject, aged 28 years.The results are promising, taking into account

that no specialized hardware was used. However, tests on a larger number of users are necessary in

order to draw solid conclusions regarding the performance of the proposed system.


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16. Determination of the Physical State of Drug in Furosemide-Eudragit Microspheres A. Ostróżka-Cieślik1, B. Sarecka-Hujar1, T. Krzykawski2

1Department of Pharmaceutical Technology, Chair of Applied Pharmacy, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec Medical University of Silesia, Poland 2Department of Earth Sciences, University of Silesia, Poland

Corresponding Author: A Ostróżka-Cieślik, [email protected] Keywords: Microspheres, Scanning electron microscopy, X-ray powder diffractometry


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17. Development and Evaluation of a Portable Spirometer, Implementing Calorimetric Anemometry Principle S. Diamantaras, T. Koutsis, I. Famelis, G. Kaltsas Department of Electronic Engineering, Technological Educational Institute of Athens, Greece

Corresponding Author: T. Koutsis, [email protected] Keywords: Spirometer, Calorimetric anemometry, Electronic interfacing, FEA modeling


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18. Devices and Tasks of Objective Dynamic Balancing Assessment – Results of a Systematic Literature Review B. Petró1, A. Papachatzopoulou2, R. M. Kiss1

1Department of Mechatronics, Optics and Mechanical Engineering Informatics, Budapest University of

Technology and Economics, Hungary 2Department of Mechanical Engineering, University of Thessaly, Greece

Corresponding Author: R M Kiss, [email protected]

Keywords: Dynamic balance, Balancing task, Balancing device, Balance assessment, Postural control, systematic review

Static posturography is often complemented with dynamic balancing ability assessment. However, no

systematic literature review had been carried out to identify all objective dynamic balancing devices

and tasks. In this poster, we present the results of a systematic search of the literature. The aim of this

work is to identify and categorize existing objective methods of dynamic balancing ability assessment

with an emphasis on the balancing devices and tasks being used. Three major scientific literature

databases (Science Direct, Web of Science, PLoS ONE) and additional sources had been used. Studies

had to use a dynamic balancing device and task described in detail. Evaluation had to be based on

objectively measureable parameters. Functional tests without instrumentation evaluated exclusively

by a clinician were excluded. A total of 69 articles were included. The data extracted during full-text

assessment were: author and date; the balancing device with the balancing task and the measured

parameters; the health conditions, size, age and sex of participant groups; follow-up. A variety of

dynamic balancing assessment devices were identified and categorized as 1) Solid ground, 2) Balance

board, 3) Rotating platform, 4) Horizontal translational platform, 5) Treadmill, 6) Computerized

Dynamic Posturography, and 7) Other devices. The identified dynamic balancing assessment methods

are offered as a catalogue of possible methods to complement static assessments used in studies

involving postural control.

Acknowledgement

This project is supported by the Hungarian Scientific Fund K083650.


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19. Dosimetric Validation of the Convolution and TMR 10 Dose Algorithms of the GammaPlan Treatment Planning System A. Logothetis1, E. Zoros1, E. P. Pappas1, E. Pantelis1, A. Dimitriadis2, I. Paddick2, P. Karaiskos1

1Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Greece

2Medical Physics Limited, London, UK

Corresponding Author: P Karaiskos, [email protected] Keywords: Stereotactic radiosurgery, Gamma Knife, Monte Carlo, Trigeminal neuralgia

Gamma Knife (GK) dosimetry has been traditionally performed using water-based algorithms. While

these algorithms have been validated for the majority of lesions within brain, their accuracy in lesions

near the skull or tissue inhomogeneities has been questioned. Recently the GK vendor introduced a

Convolution dose algorithm that takes into account tissue inhomogeneities and can be used

alternatively to the classical water-based algorithm. Since this constitutes a paradigm shift in GK

dosimetry, validation of the proposed Convolution dose algorithm is necessary.

In this work, we used the single sector phase space source models created using an EGSnrc user code

developed in-house to perform Monte Carlo (MC) dosimetric calculations for the validation of the

Convolution dose engine installed in the GammaPlan treatment planning system (TPS, TMR-10). This

was performed for a trigeminal neuralgia case involving a single shot dose distribution of 90 Gy at

Dmax at the right trigeminal nerve. The patient geometry was modelled inside the MC simulations

using an orthogonal lattice geometry with fine spatial resolution using the DICOM-CT images, DICOM-

RT plan, and DICOM-RT structures of the patient plan. The density of each voxel was obtained using

the calibration curve of the CT and material description. MC derived dose distributions in the patient

anatomy were compared with corresponding Convolution and TMR-10 TPS calculations in terms of 1D

dose profiles, 2D/3D dose distributions and DVHs for targets and organs at risk (i.e., brain stem).

Comparison revealed that while Convolution and MC calculations were found in agreement, the TMR-

10 calculated dose distributions differed by ~5%, which could be mainly attributed to the fact that it

does not take into account the skull-bone inhomogeneity. The use of MC simulation method for

patient plan verification in GK applications is feasible and work is in progress for multiple shot

irradiations in cases where inhomogeneities could influence significantly dose distributions.

Acknowledgement

-This work was supported by computational time granted from the Greek Research & Technology

Network (GRNET) in the National HPC facility – ARIS – under project ID pr003021.

-This work was financially supported by the State Scholarships Foundation of Greece through the

program Research Projects for Excellence “IKY/SIEMENS”.


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20. EBT3 Film Dosimetry for the QA of kV X-ray Radiation Therapy H. Prentou1, K. Kourioti2, E. Zoros1, P. Papagiannis1

1Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Greece 2Physics Department, National and Kapodistrian University of Athens

Corresponding Author: P Papagiannis, [email protected] Keywords: Dosimetry, Film, EBT3, kV x-rays

Besides the simplicity of clinical applications, the low photon energy in KV x-ray beams used in

superficial radiation therapy are associated with dosimetry problems including detector intrinsic and

absorbed dose energy dependence, cavity theory corrections, and volume averaging.

In this work, EBT3 film was calibrated in all nine beam qualities of an X-Strahl 200 unit (HVL: 1mm Al

to 2 mm Cu). Film samples from the same batch were scanned using an EPSON V750 Pro flatbed

scanner pre- and post-irradiation to calibrate dose response in terms of net optical density in each

color channel versus delivered water kerma in air (0.5, 1, 2, 3 Gy). A polynomial fitting function was

used to derive corresponding calibration functions which were found to vary beyond statistical

uncertainties with beam quality. Absorbed dose sensitivity was found adequate in the studied kerma

range for the red and green channels, and higher for the former in accordance with the literature.

Experimental single channel dosimetry uncertainty was on the order of 2% and 4% for the red and

green channels. Film samples were also irradiated on the surface of a water equivalent phantom and

relative backscatter factors for the beam qualities of the unit were verified within experimental

uncertainties.


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21. Examining the Spatial Frequency Components of a Digital Dental Detector A. Anastasiou1, C. Michail1, 2, V. Koukou2, N. Martini2, A.Bakas2, 3, F. Papastamati1, P. Maragkaki1, L.

Lavdas2, 3, G. Fountos1, 2, I. Valais1, 2, N. Kalyvas1, 2

1Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece 2Laboratory of Radiation Physics Materials Technology and Biomedical Imaging, Technological

Educational Institute of Athens, Greece 3Department of Medical Radiologic Technologists, Technological Educational Institute of Athens,

Greece

Corresponding Author: N Kalyvas, [email protected] Keywords: Dental radiography, Digital detector, MTF

Digital X-ray detectors are widely used in dental radiography. The scope of this work is the

examination of the spatial frequency component of a dedicated dental CMOS detector. A commercially

available SCHICK CDR CMOS detector was irradiated at a Del Medical Eureka X-ray system at 60kV and

70kV. The irradiation setup included images of an edge, for Modulation Transfer Function (MTF)

calculation. The air-KERMA was measured with an RTI PIRANHA X-ray multimeter. The images were

evaluated in ‘for presentation’ format with the use of ImageJ software. This detector demonstrated a

slightly steeper X-ray response curve (pixel value vs air kerma) from a similar detector reported in

literature (N. Kalyvas et a.l Physica Medica,32, Suppl.3, 286-287, 2016). The linear range of the

detector was found in the range 13µGy-183µGy at 60 kV and 18µGy-180µGy at 70 kV. By inspecting

the MTF curves it was found that MTF(6lp/mm)60kV=0.29 and MTF(6lp/mm)70kV=0.25. The inspection of

NNPS showed similar low noise components at irradiation conditions of (60 kV, 73.4µGy) and (70kV,

100.8µGy). Our results indicate that this detector presents comparable performance at both kV,

although its X-ray response (pixel value vs air KERMA) was not equal to previously published results,

for the same detector type.


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22. Eye-Related Hazards Associated with Blue Light Radiation Emitting Modern Lighting Sources, Mobile Screen, Computers and Tablets I. Sianoudis1, G. Mitsou2, D. Melanitis1, I. Valais3

1Department of Optics & Optometry, Technological Educational Institute (TEI) of Athens, Greece 2Department of Energy Technology Engineering, Technological Educational Institute (TEI) of Athens,

Greece 3Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece

Corresponding Author: I Sianoudis, [email protected] Keywords: Blue light effect, Eye protection, Radiation sources

The biological effect of blue light on the eye, although it has been known for a long time, has acquired

a particular importance in recent years and is at the forefront of discussions, mainly due to the rapid

spread of LED technology on which new sources of room lighting are based. Particularly, the

manufacture of television screens, computers, mobile phones and tablets also are LED-based blue light

sources, emitted a disproportionately large amounts of blue light in the area around 450 nm, relative

to the other spectral components of white light, with the result, that the eye is exposed to ever greater

intensities of this spectral range. In this work, we performed spectroscopic measurements to quantify

in absolute amount the light intensity of blue light coming from different sources of illumination and

devices, as opposed to the rest of the spectrum, while we estimated the possible dose to be taken by

an average worker, in his workplace, spent a lot of time in front of a computer screen. Additionally, we

also tested optical glasses proposed for eye blue-protection, comparing with maximum permissible

limits established in European regulations.


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23. Histology Image Collection Library D. Glotsos1, S. Kostopoulos1, P. Ravazoula2, D. Cavouras1

1Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece 2Department of Pathology, University Hospital of Patras, Greece

Corresponding Author: D Glotsos, [email protected] Keywords: Microscopy, Histopathology, Brain, Breast, HPV, Cancer

Tissue biopsy examination is considered as the most critical step in diagnosis of complicated diseases,

such as cancer. A small region is removed from the most representative region of tumor for

microscopy examination. Due to the complexity of the biopsy material, the definition of distinct

boundaries between different diagnostic boundaries is difficult to be performed. Computer- aided

diagnostic systems have been shown to assist histopathologist towards more accurate decisions. In

this study, the Histopathology Image Collection Library is presented, which is an ongoing effort to

create a reference image database for research in histopathology and computer-aided diagnosis. The

collection consists of 3831 histological images of brain, breast and cervical cancer collected from the

University Hospital of Patras, Greece. Images were generated using a Leica DM2500 microscope

coupled to a DFC420 CCD digital camera at 40x and 20x magnifications. The library can be accessed at

http://medisp.bme.teiath.gr/hicl/ and it is free for academic use. The library may be used for

numerous applications, such as for testing the reliability of decision support systems, fine tuning of

image processing algorithms, investigation of potential correlation between imaging findings and

other related fields in image processing and computer aided diagnosis in histopathology.

Acknowledgement




http://medisp.bme.teiath.gr/hicl/

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24. X-ray Irradiation Affects the Biomechanical Properties of Human Red Blood

Cells E. Spyratou1, J. Antonakos1, K. Platoni1, M. Makropoulou2, E. Efstathopoulos1

12nd Department of Radiology, Medical School, National and kapodistrian University of Athens,

Athens, Greece 2Physics Department, Faculty of Applied Mathematical and Physical Sciences, National Technical

University of Athens, Zografou Campus, Athens, Greece

Corresponding Author: S Ellas, [email protected] Keywords: X-ray irradiation, Red blood cells, Biomechanical properties

In this research work, we investigate the effect of ionizing radiation on the biomechanical properties of

erythrocyte cells. The motivation for this research effort has two tentative objectives. The first is the

investigation of any possible effect of radiation on the deformability of red blood cells (RBC), namely

erythrocytes, which lack DNA, thus separating the radiobiological effect from DNA damage or from the

interference of intracellular membranes. The second goal, if the previous results in an observable

radiobiological effect in red blood cells, could be the development of a low-cost method to screen

people for exposure to radiation. RBCs are a suitable candidate for monitoring the radiation effect for

one more reason: they are the “War correspondent” for the whole body, since circulates all over the

body. The biomechanical properties of RBC will be probed by using the advanced microscopic

techniques of “line optical tweezers” and Atomic Force Microscopy which is ideally suited for single cell

micromanipulation providing simultaneously information about the mechanical properties of the cells.

Our finding indicate that X-ray irradiation affect the biomechanical properties of red blood cell

cytoskeleton.

Acknowledgment

The authors would like to thank the “IKY FELLOWSHIPS OF EXCELLENCE FOR POSTGRADUATE STUDIES

IN GREECE”


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Friday 13, October 2017

Oral Sessions (9:30 – 18:00)

9:30 – 11:00 Session 1. Radiation Dosimetry Session Chairpersons: N. Kalyvas, I. Valais

9:30 - 9:45 Foetus Dose Estimation in Typical Diagnostic Nuclear Medicine Procedures M-A. Vasileiou, A. Stefanoyiannis, X. Geronikola Trapali, I. Armeniakos, T. Liotsou, E. Efstathopoulos,

S. Chatziioannou

Department of Radiology, Nuclear Medicine Division, University General Hospital of Athens

“Attikon”, Greece

Corresponding Author: A P Stefanoyiannis, [email protected] Keywords: Nuclear medicine, Absorbed foetal dose, Pregnancy, Foetus

Several modalities are currently utilized for diagnosis and therapy, based on appropriate application of

x-rays (Diagnostic Radiology & Radiotherapy) and gamma-rays/beta particles (Nuclear Medicine). In

any case, the possibility of pregnancy in women of childbearing age should be considered. The

radiation protection of a pregnant woman and therefore, radiation protection of the corresponding

foetus is of outmost importance. Based on radiation risk, the termination of pregnancy is not justified

if foetal doses are below 100 mGy. In the case of Nuclear Medicine, the pregnant patient may be even

more apprehensive, realizing that an administered radioactive material has been incorporated into her

body, that it will be there for some time and that it may potentially cross the placenta to the foetus.

For that reason, our purpose was to estimate the absorbed doses to uterus in an adult pregnant

patient from various diagnostic examinations of Nuclear Medicine, and compare them with published

typical foetal doses reported by IAEA.

Dosimetry information to uterus from technical leaflets of 9 kits for Nuclear Medicine diagnostic

procedures were used to estimate the absorbed doses, based on the administered activity in our

division.

The absorbed doses in uterus and therefore in a corresponding foetus for 9 diagnostic examinations

ranged from 0.36 to 14.8 mGy.

Our estimated absorbed doses were found to be well below the dose constraint of 100 mGy, and

similar with those reported by IAEA. Pregnancy termination in case of similar foetal doses is not

justified.

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9:45 - 10:00 Development of a Phase Space Source Model for Monte Carlo Dosimetry in Gamma Knife Applications A. Logothetis1, E. P. Pappas1, E. Zoros1, E. Pantelis1, A. Dimitriadis2, I. Paddick2, P. Karaiskos1

1Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 75

Mikras Asias, 115 27, Athens, Greece 2Medical Physics Limited, London, UK

Corresponding Author: P Karaiskos, [email protected] Keywords: Stereotactic radiosurgery, Gamma Knife, Monte Carlo, Dosimetry

Dosimetric calculations in Gamma Knife (GK) applications are traditionally performed using water-

based algorithms. While these algorithms have been validated for the majority of lesions within brain,

their accuracy in lesions near the skull or tissue inhomogeneities has been questioned. Recently, the GK

vendor introduced a Convolution dose algorithm which takes into account tissue inhomogeneities.

Since this constitutes a paradigm shift in GK dosimetry, validation of the proposed Convolution dose

algorithm is necessary.

The purpose of this work is to develop and validate a GK Perfexion source model to be used in

consequent Monte Carlo (MC) dosimetry calculations for the validation of the Convolution algorithm.

While MC is considered the gold standard in dose calculations, increased computational times are

required to obtain low uncertainty dosimetry results. To improve efficiency, single sector Phase Space

(PHSP) source models were created for each field size using a new EGSnrc C++ user code developed in-

house. PHSP data were scored below the secondary collimator system of the GK unit. A number of 171

× 109 photons were generated in the 60Co sources of one sector assuming isotropic emission and only

0.087‰, 0.023‰ and 0.007‰ of them passed the secondary collimator and were stored in the PHSP

file for the 16, 8 and 4mm collimator size, respectively.

Dose distributions in a spherical water phantom of a single sector and 8 sector cases for all available

collimator sizes were calculated using PHSP models and compared with corresponding results

obtained by MC simulations of the full GK geometry as well as the water-based and Convolution

algorithms. An excellent agreement was found between the studied dose calculation techniques.

Output factors of the 4 and 8mm collimators were respectively found equal to 0.8193 and 0.8925,

which are in agreement with corresponding published values.

The developed GK single sector PHSP model was found to be able to reproduce accurately and more

efficiently (of the order of 1000) dose distributions in GK applications.

Acknowledgement

-This work was supported by computational time granted from the Greek Research & Technology

Network (GRNET) in the National HPC facility – ARIS – under project IDs pr002037 and pr003021.


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10:00 - 10:15 Patient Radiation Dose in Extracorporeal Lithotripsy A. Moulita1, G. Messaris1, A. Hadjiconstanti1, A. Lekatou1, E. Liatsikos2, G. Panayiotakis1

1Department of Medical Physics, School of Medicine, University of Patras, Greece 2Department of Urology, School of Medicine, University of Patras, Greece

Corresponding author: G Panayiotakis, [email protected] Keywords: Urology, Lithotripsy, Patient Dose

A modern interventional procedure in urology is the extracorporeal shock wave lithotripsy (ESWL). This

procedure is fluoroscopically guided and thus patients are exposed to radiation. In this study, the

patient dose in ESWL is evaluated. Twenty-one patients participated in this study. The procedures were

carried out at the Department of Urology at the University Hospital of Patras, utilizing a Dornier

Lithotripter S II. The patient characteristics (sex, age, BMI), the fluoroscopy time (FT) and the dose-

area product (DAP) were recorded, whilst the effective dose (ED) was estimated using appropriate

conversion coefficients (CC). The mean FT was 3.49 min, the mean DAP value was 486.3 cGy*cm2 and

the mean ED value was 0.66 mSv. The mean FT value was similar to corresponding values previously

reported, whilst the mean DAP and ED values were similar or lower than the corresponding values

reported, mainly due to the modern system used, in combination with the high experience of the

operators. The values reported could contribute in the effort for further optimization of the technique

and radiation protection of the patients.


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10:15 - 10:30 Automated Measurements of Metabolic Tumor Volume and Metabolic Parameters in Lung PET/CT Imaging F. Orologas, P. Saitis, M. Kallergi


Corresponding Author: M Kallergi, [email protected] Keywords: PET/CT hybrid imaging, Metabolic tumor volume, SUV, TLG automated measurements Patients with lung tumors or inflammatory lung disease could greatly benefit in terms of treatment

and follow-up by PET/CT quantitative imaging, namely measurements of metabolic tumor volume

(MTV), standardized uptake values (SUVs) and total lesion glycolysis (TLG). The purpose of this study

was the development of an unsupervised or partially supervised algorithm using standard image

processing tools for measuring MTV, SUV, and TLG from lung PET/CT scans.

Automated metabolic lesion volume and metabolic parameter measurements were achieved through

a 5 step algorithm: (i) The segmentation of the lung areas on the CT slices, (ii) the registration of the

CT segmented lung regions on the PET images to define the anatomical boundaries of the lungs on the

functional data, (iii) the segmentation of the regions of interest (ROIs) on the PET images based on

adaptive thresholding and clinical criteria, (iv) the estimation of the number of pixels and pixel

intensities in the PET slices of the segmented ROIs, (v) the estimation of MTV, SUVs, and TLG from the

previous step and DICOM header data. Patient data for training and testing the algorithm were

acquired with a Biograph 6 (Siemens Healthcare, DE) PET/CT system using the same, whole-body

imaging protocol.

Lung area segmentation on the CT slices was better achieved with semi-supervised techniques because

unwanted structures could be avoided, something that leads to overestimates of the disease in the

subsequent PET segmentation. Lung segmentation results agreed with the lung volumes published in

the literature while the agreement between expert and algorithm in the segmentation of the lesions

was around 88%. Segmentation results depended on the image resolution selected for processing. The

clinical parameters SUV (either mean or max or peak) and TLG estimated by the segmented ROIs and

DICOM header data provided a way to correlate imaging data to clinical and demographic data.

Automated MTV, SUVs, and TLG measurements offer powerful analysis tools in PET/CT hybrid imaging

of the lungs. Custom-made algorithms are often a better approach than the manufacturer’s general

analysis software at much lower cost. Relatively simple processing techniques could lead to

customized, unsupervised or partially supervised methods that can successfully perform the desirable

analysis and adapt to the specific disease and requirements.

Acknowledgement

The authors would like to thank the members of the Division of Nuclear Medicine of the Biomedical

Research Foundation of the Academy of Athens and the 2nd Pulmonary Medicine Department of

“Attikon” University Hospital for providing data and ground truth information for the training and

testing of the algorithms.


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10:30 - 10:45 Influence of Multiple Brain Metastases’ Size and Number on the Quality of SRS – VMAT Dose Delivery G. Prentou1, E. Koutsouveli2, E. Pantelis1, P. Papagiannis1, E. Georgiou1, P. Karaiskos1

1Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Greece 2Medical Physics Department, Hygeia Hospital, Athens, Greece

Corresponding Author: P Karaiskos, [email protected] Keywords: Multiple brain metastases, Stereotactic radiotherapy, Radiosurgery, Vmat Stereotactic radiosurgery with volumetric modulated arc therapy (SRS-VMAT) has recently been

introduced for treatment of multiple brain metastases with a single isocenter. The technique’s high

efficiency is nevertheless dependent of metastatic tumors’ characteristics such as size and number. In

this work the impact of the metastases’ size and number on the plan quality indices clinically used for

plan evaluation and acceptance is investigated.

Fifteen targets with a diameter of 1 cm and average volume of 0.7 cm3 and ten targets with a

diameter of 2 cm and average volume of 6.5 cm3 were contoured on an anonymized patient CT

dataset, in Monaco (Elekta) treatment planning system. VMAT plans for different target volumes (1

and 2 cm in diameter) and various target numbers (1–15) were generated using four non-coplanar

arcs and the Agility (Elekta) linear accelerator (5 mm MLC width) using a Monte Carlo dose calculation

algorithm and 1mm dose calculation grid resolution.

Conformity index (CI), gradient index (GI) and heterogeneity index (HI) were determined for each

target. High quality plans were created for both 1 cm and 2 cm in diameter targets for limited (<6)

number of targets per plan. For increased number of irradiated targets (>6) both CI and GI, clinically

used for plan evaluation and acceptance, were found to deteriorate.

Acknowledgement

G. Prentou is financially supported by the Hellenic Foundation of Research and Innovation (ELIDEK).


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11:30 – 13:00 Session 2. Nanotechnology in Biological Sciences Session Chairpersons: E. P. Efstathopoulos, K. Platoni

11:30 - 11:43 Two Dimensional Drug Diffusion between Nanoparticles and Fractal Tumors S. Samioti1, K. Karamanos2, A. Tsiantis3, A. Papathanasiou4, I. Sarris5

1Department of Mechanical Engineering, University of Thessaly, Greece 2Department of Energy Technology, TEI of Athens, Greece 3Department of Mechanical Engineering, University of Thessaly, Greece 4Department of Mechanical Engineering, University of Thessaly, Greece 5Department of Energy Technology, TEI of Athens, Greece

Corresponding Author: S Samioti, [email protected] Keywords: Cancer tumor, Drug delivery, Diffusion, Finite Elements method, Laplacian field, Triangular Von Koch curve

Drug delivery by nanoparticles is one of the most promising medical application in nanotechnology to

treat cancer. It is observed that drug released by the nanoparticles to cancer tumors may be driven by

diffusion. A fractal tumor boundary of triangular Von Koch shape is considered here and the diffusion

mechanism is studied for different drug concentrations and increased fractality. A higher order Finite

Elements method based on Fenics library is incorporated in fine meshes to fully resolve the irregular

boundaries. Quantities like mass transfer rates and entropy production are calculated in an up to six

orders fractal iteration boundaries. We observed that diffusion rate diminishes for successive

prefractal generations. Also, the entropy production around the system changes greatly from the first

fractal iteration to the sixth. Results indicate with precision where the active sites are, in which most of

the diffusion takes place and the drug arrives to the tumor.


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11:43 - 11:56 Applications of Nanotechnology in Radiological Imaging A. Ploussi1, K. Platoni1, E. Efstathopoulos1

2nd Department of Radiology, University General Hospital “Attikon”, School of Medicine, National


Corresponding Author: E P Efstathopoulos, [email protected] Keywords: Nanoparticles, Radiological imaging, Contrast agents

Modern medical imaging modalities like CT, MRI and US offer the potential for early detection and

characterization of several diseases. To increase the sensitivity and specificity of imaging modalities,

intravenous contrast agents are used. However, the conventional contrast agents are inadequate to

detect molecular targets because of their low sensitivity, their extremely short circulation plasma time,

and their rapid renal excretion.

To overcome these limitations, in recent years, the scientific research has focused on the development

of nanoparticle-based contrast agents. Nanoparticle-based contrast agents have several advantages

over the conventional contrast agents including higher detection sensitivity, better biocompatibility,

lower toxicity and selective localization. Nanoparticles have significantly different properties and

mechanism of action in relation to conventional-based contrast agents.

The purpose of the current study is to summarize the main types of nanoparticle contrast agents for

each imaging modality and provide the potential role and the applications of nanoparticle-based

contrast agents in clinical and preclinical imaging.


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11:56 - 12:09 Nanoparticles: Nanotoxicity Aspects E. Vlastou1, 2, M. Gazouli 3, A.Ploussi2, K. Platoni2, E. Efstathopoulos2

1Athens General Children's Hospital “Pan. & Aglaia Kyriakou”, Athens, Greece 22nd Department of Radiology, University General Hospital “Attikon”, School of Medicine, National

and Kapodistrian University of Athens, Greece 3Department of Basic Medical Science, Laboratory of Biology, School of Medicine, University of

Athens, Greece

Corresponding Author: E P Efstathopoulos, [email protected] Keywords: Nanotechnology, Nanoparticles, Toxicity, Nanotoxicology, Nanotoxicity

The giant steps towards Nanosciences dictate the need to gain a broad knowledge about not only

beneficial but also noxious properties of Nanomaterials. Apart from the remarkable advantages of

Nanoparticles (NPs) in medicine and industry, there have been raised plenty of concerns about their

potential adverse effects in living organisms and ecosystems as well. Without a doubt, it is of critical

importance to ensure that NPs medical and industrial applications are accompanied by the essential

safety so that the balance will be tilted in favor of the profits that society will earn.

However, the evaluation of NPs toxic effects remains a great challenge for the scientific community

due to the wealth of factors that Nanotoxicity depends on. Size, surface area, dosing, shape, surface

coating and charge and bulk material are the basic parameters under investigation to assess the risk

involved in NPs usage. Our purpose is to highlight NPs’ physical and chemical properties responsible

for induced toxicity, describe the mechanisms that take place in their interaction with cells and organs

and finally report the potential harmful consequences that may result from the innovative applications

of nanomaterials.


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12:09 - 12:22 Physico-Chemical Characterization and Basic Research Principles of Mixed/Chimeric Delivery Platforms N. Pippa1, 2, S. Pispas2, C. Demetzos1

1Department of Pharmaceutical Technology, Faculty of Pharmacy, National and Kapodistrian

University of Athens, Greece 2Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens, Greece

Corresponding Author: N Pippa, [email protected] Keywords: Mixed/chimeric systems, Physicochemical characterization, Thermal analysis, Light scattering techniques Mixed/chimeric systems are multi-compartment drug delivery vehicles composed of different in nature

materials such as lipids and polymers and/or lipids and dendrimers. Several physicochemical

techniques are used in order to study the interactions between those materials. The most important

techniques including light scattering (dynamic, static, and electrophoretic), thermal analysis [especially

differential scanning Calorimetry (DSC)], and imaging techniques are presented for the physico-

chemical characterization of chimeric systems. These techniques are used extensively for the detailed

characterization of chimeric systems, in the research and development of innovative nanocarriers and

are required from the regulatory authorities. Several examples will be delivered focused on the

interactions between the different materials, the size and the size distribution of chimeric/mixed

vesicles and the morphology/structure of these drug delivery vesicles. The physicochemical

characteristics of nanosystems (the nanoformulation system) play a key role in the administration,

distribution, metabolism, and excretion (ADME profile) of the encapsulated active pharmaceutical

ingredient. It should be noted that the minimum requirements of nanosimilar products (follow-on

nanomedicines) are the highly similar physicochemical characteristics (i.e. size, size distribution, ζ-

potential, etc.). In conclusion, the data from the evaluation of physicochemical characteristics of

chimeric/mixed systems are important for their behavior in biological media and in human body.


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12:22 - 12:35 Applications of Nanotechnology in Nuclear Medicine Imaging

C. Tsoukalas, P. Bouziotis

Radiochemical Studies Laboratory, Institute of Nuclear & Radiological Sciences & Technology,

Energy & Safety, National Center for Scientific Research “Demokritos”, Athens, Greece

Corresponding Author: P Bouziotis, [email protected] Keywords: Nanoparticles, Radiolabeling, SPECT, PET Many cancers are characterized by low survival rates, which can be attributed to late diagnosis. Sixty

to 70 % of patients first diagnosed with cancer are already in the metastatic phase of the disease. The

development of novel imaging tools with improved imaging characteristics would lead to an early

identification of the disease and consequently, to improved patient management. Nanoparticles

possess unique characteristics that make them well-suited as probes for molecular imaging.

Engineering of a nanoparticle surface chemistry allows the surface area to bear therapeutic molecules,

imaging agents or targeting ligand. A single nanoparticle can be conjugated with a large number of

targeting ligands, increasing the affinity of the nanoparticle to its biological target through a

phenomenon known as multivalency. Subsequently, the nanoparticle can be linked to a large number

of reporter molecules (e.g.radionuclides) either via the attached targeting ligand or via an adequate

chelating molecule conjugated onto the NP surface, thus increasing the signal-to-noise in imaging

applications. Therefore, nanoparticles are superior to traditional SPECT/PET imaging probes.

Radiolabeled nanoparticles can circulate for longer periods of time than small molecule SPECT/PET

tracers, thus carrying a larger radionuclide payload.


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12:35 - 12:48 Advances in Drug Delivery Nano Systems C. Demetzos

Department of Pharmacy, Section Pharmaceutical Technology, Laboratory of Pharmaceutical

Technology and nanoTechnology, National and Kapodistrian University of Athens, Greece

Corresponding Author: C. Demetzos, [email protected] Keywords: Liposomes, Drug delivery, Physicochemical characterization, Chimeric nanosystems Advanced Drug Delivery nanoSystems (aDDnSs) are self-assembled artificial systems prepared by the

combination of two or more different in nature bio-materials, such as lipids and polymers. They have

recently appeared in the research field and their advantages are: their ability to modulate the

encapsulation efficiency, to modulate the release profile of the encapsulated drug, their

responsiveness in external stimuli and to improve the targeting process. Molecular interactions

between the encapsulated drug and the lipid bilayer membrane have decisive influence on the

liposomal formulation process and the drug release from the liposomes, which determine partitioning,

allocation, orientation, and conformation of the drug in the bilayer membrane and thus plays an

important role in transport, distribution, accumulation, and eventually, efficacy of the drug delivery

nanosystem. As a result, it is of great importance to determine the interactions between the polymers

and / or the lipid components with the drug after its encapsulation, as well as the mechanism of drug

release from the formulation. However, physichochemical and thermodynamic methods as well as

electron microscopy methods have been carried out in order to determine such interactions as well as

the self-assembly process and the biophysical profile of the whole nanosystem. The recent advances in

the development of lipid- (i.e. liposomes, niosomes, solid lipid nanoparticles etc.) and polymer-

(micelles, polymersomes, dendrimers, polymeric nanoparticles, hydrogels etc.) based nanocarriers will

be analyzed on the basis of pharmaceutical nanotechnology considerations, in vitro and in vivo

evaluation as well as clinical perspectives. The advantages of cancer nanotherapy are drug targeting,

controlled and site specific release and targeting, preferential distribution within the body and

improved transport across biological barriers. Chimeric/Mixed nanocarriers as advanced drug delivery

nanoplatforms can be considered as new therapeutic outcomes in cancer nanotherapy that could be

able to deliver anticancer drugs to specific tissues. They can improve the

pharmacokinetics/pharmacodynamics behavior of antitumor molecules and affect their total

bioavailability, due to their physicochemical and mechanical properties, which depend on the

structural characteristics of nanocarriers.


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12:48 – 13:00 Block Copolymer based Protein Nanocarriers: Hierarchical Self-Assembly and Responsiveness A. Papagiannopoulos, S. Pispas

Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens, Greece.

Corresponding Author: A Papagiannopoulos, [email protected] Keywords: Small angle neutron scattering, Self-assembly, Nanoencapsulation, Stimuli responsive polymers

Polymeric nanostructures have unique properties for applications in targeted drug delivery through

biocompatible, biodegradable and non-toxic routes. Their ability to respond to external triggers as

temperature and pH allows them for “smart” release while their amphiphilic character is often used

for encapsulation and solubilization of hydrophobic drugs. Small angle scattering methods are

powerful noninvasive techniques with the ability to resolve the morphology at the nanoscale (1-

1000nm). In this paper, research on thermoresponsive self-assembled block copolymers and their

interactions with the model protein lysozyme based on small angle neutron scattering (SANS) and light

scattering (LS) will be presented aiming at developing smart protein/peptide nanocarriers. Lysozyme

can be considered as both a bioactive compound and a nanocomponent that can be loaded together

with other substances. SANS shows that the self-assembled block copolymer soft nanoparticles form

hierarchically organized structures at multiple length-scales in a controllable manner. More

importantly their response to temperature depends on the length scale. When lysozyme is added to

the solutions it attaches on the macromolecular nanoparticles and may alter their hierarchical

organization depending on its mode of attachment. Additionally, it influences the temperature

response of the macromolecular aggregates in a controllable way. These works demonstrate the

application of scattering techniques on model nano-encapsulation systems and the findings can be

applied on other polymer-drug complexes of current biomedical interest.


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14:00 – 15:30 Session 3. Therapeutic-Clinical Applications Session Chairpersons: E. C. Ventouras, G. K. Matsopoulos

14:00 - 14:13 Review and Comparison of Geometric Distortion Correction Schemes in MR Images Used in Stereotactic Radiosurgery Applications

E. P. Pappas1, D. Dellios1, 2, I. Seimenis2, A. Moutsatsos1, E. Georgiou1, P. Karaiskos1

1Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Greece 2Medical Physics Laboratory, Medical School, Democritus University of Thrace Alexandroupolis,

Greece

Corresponding Author: P Karaiskos, [email protected] Keywords: MRI, Geometric distortion, Spatial accuracy, Stereotactic radiosurgery

In Stereotactic Radiosurgery (SRS), MR-images are widely used for target localization and delineation

in order to take advantage of the superior soft tissue contrast they exhibit. However, spatial dose

delivery accuracy may be deteriorated due to geometric distortions which are partly attributed to

static magnetic field inhomogeneity and patient-induced chemical shift and susceptibility related

artifacts. Several post-imaging patient-specific distortion correction schemes have been proposed

which mainly employ the reversal of read gradient polarity. The scope of this work is to review,

evaluate and compare the efficacy of two proposed correction approaches.

A specially designed phantom which incorporates 947 control points (CPs) for distortion detection was

utilized. The phantom was MR scanned at 1.5T (Philips-Achieva) using the head coil and the clinically

employed pulse sequence for SRS treatment planning. An additional scan was performed with identical

imaging parameters except for reversal of read gradient polarity. In-house MATLAB routines were

developed for implementation of the signal integration and average-image distortion correction

techniques. The mean CP locations of the two MR scans were regarded as the reference CP

distribution. Residual distortion was assessed by comparing the corrected CP locations with

corresponding reference positions.

Mean absolute distortion on frequency encoding direction was reduced from 0.34mm (original

images) to 0.15mm and 0.14mm following application of signal integration and average-image

methods, respectively. However, a maximum residual distortion of 0.7mm was still observed for both

techniques. The signal integration method relies on the accuracy of edge detection and requires 3-4

hours of post-imaging computational time. The average-image technique is a more efficient

(processing time of the order of seconds) and easier to implement method to improve geometric

accuracy in such applications.

Acknowledgement

This work was financially supported by the State Scholarships Foundation of Greece through the

program ‘Research Projects for Excellence IKY/SIEMENS’.


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14:13 - 14:26 Evaluation of Quantitative MRI Sequences for T1 Brain Mapping P. Tsialios1, C. Pernet2, M. Thrippleton2, A. Glatz2

1Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece 2Centre for Clinical Brain Sciences, University of Edinburgh, UK.

Corresponding Author: P Tsialios, [email protected] Keywords: T1-mapping, Brain imaging, Inversion recovery, MP2RAGE, Variable flip angle

T1 mapping constitutes a quantitative MRI technique finding significant application in brain imaging.

It allows evaluation of contrast uptake, blood perfusion, volume, providing a more specific biomarker

of disease progression compared to conventional T1-weighted images. While there are many

techniques for T1-mapping there is a wide range of reported T1-values in tissues, raising the issue of

protocols reproducibility and standardization.

The gold standard for obtaining T1-maps is based on acquiring IR-SE sequence. Widely used

alternative sequences are IR-SE-EPI, DESPOT-HIFI, VFA and MP2RAGE that speed up scanning and

fitting procedures. A custom MRI phantom was developed to assess the reproducibility and accuracy of

the different methods. All scans were performed using a 3T Siemens Prisma scanner. The acquired

data processed using two different codes.

The IR-SE sequence has robust replicability (r=0.993-0.999, 95%CI: 0.971-1, p<0.001). The two codes

give similar results for IR-SE and IR-SE-EPI according to Bland-Altman analysis. T1-values extracted

from IR-SE-EPI, DESPOT-HIFI and MP2RAGE T1-maps do not differ significantly from IR-SE

counterparts. Contrariwise, VFA T1-maps give significantly higher T1-values in comparison to the gold

standard (mean difference=201ms).

MP2RAGE, IR-SE-EPI and DESPOT-HIFI sequences can be considered as alternative and time-efficient

methods for acquiring accurate T1-maps of the human brain.

Acknowledgement

The authors would like to thank Nikola Stikov, Assistant Professor of Biomedical Engineering at

Polytechnique Montréal for providing them the "T1Mapping Matlab package". Moreover, part of this

work was partially supported by European Union resources under the framework of the TRIMAGE: "A

dedicated trimodality (PET/MR/EEG) imaging tool for schizophrenia"project.


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14:26 - 14:39 Comparative Analysis of Methods for Extracting Vessel Network on Breast MRI Images B. Gaizer1, K. Vassiou2, E. Lavdas3, D. Arvanitis4, I. Fezoulidis2, D. Glotsos5

1Department of Mechatronics, Optics and Mechanical Engineering Informatics; Budapest University of

Technology and Economics

2Department of Radiology, Medical School of Thessaly, University Hospital of Larissa, Greece 3Department of Medical Radiologic Technology, Technological Educational Institute of Athens,

Greece 4Department of Anatomy, School of Health Sciences, University of Larissa, Greece 5Medical Image and Signal Processing Laboratory, Department of Biomedical Engineering,

Technological Educational Institute of Athens, Greece

Corresponding Author: B T Gaizer, [email protected] Keywords: Medical image processing, MRI, Breast cancer diagnosis Digital processing of MRI images aims to provide an automatized diagnostic evaluation of regular

health screenings. Cancerous lesions are proven to cause an alteration in the vessel structure of the

diseased organ. Currently there are several methods used for extraction of the vessel network in order

to quantify its properties. In this work MRI images (Signa HDx 3.0T, GE Healthcare, courtesy of

University Hospital of Larissa) of 30 female breasts were subjected to three different vessel extraction

algorithms to determine the location of their vascular network. The first method is an experiment to

build a graph over known points of the vessel network; the second algorithm aims to determine the

direction and diameter of vessels at these points; the third approach is a seed growing algorithm,

spreading selection to neighbors of the known vessel pixels. The possibilities shown by the different

methods were analyzed, and quantitative measurements were performed. The data provided by these

measurements showed no clear correlation with the presence or malignancy of tumors, based on the

radiological diagnosis of skilled physicians.

Acknowledgement

I would like to express my gratitude towards my advisor, Dimitris Glotsos, and the staff of the MEDISP

lab for hosting me, and providing me with knowledge and resources


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14:39 - 14:52 Computation of an MRI Brain Atlas from a Population of Parkinson's Disease Patients

L. Angelidakis¹, I. Papageorgiou², C. Damianou¹, M. N. Psychogios², P. Lingor³, K. von Eckardstein4,

S. Hadjidemetriou¹

1Department of electrical engineering, computer engineering and informatics, Cyprus University of

Technology, Limassol, Cyprus 2Department of diagnostic and interventional neuroradiology, University Medical Center Goettingen,

University of Goettingen, Germany 3Department of neurology, University Medical Center Goettingen, University of Goettingen, Germany 4Department of neurosurgery, University Medical Center Goettingen, University of Goettingen,

Germany

Corresponding Author: L Angelidakis, [email protected] Keywords: MRI Brain Atlas, Parkinson’s disease, Subcortical brain regions Parkinson's Disease (PD) is a chronic degenerative disorder of the central nervous system. The aim of

this work is to develop an MRI-based brain atlas representative of the PD-brain alterations for

diagnostic and interventional medical applications. The atlas aims to standardize especially the

relevant subcortical regions such as the thalamus, globus pallidus, red nucleus, substantia nigra,

putamen, and caudate nucleus. We used 3.0 T MRI brain images from 16 PD patients and 10 matched

controls. A multi-contrast atlas has been computed with the open platform 3D Slicer® using T1- and T2-

weighted images, as well as Susceptibility Weighted Images (SWI), with T1-W images being the

reference for the inter-subject non-rigid registration. Localization was achieved by co-registration with

a labeled atlas using BrainSuite® and the level sets segmentation method with ITK-Snap. The contrast

ratio of the target subcortical regions to the surrounding white matter was analyzed as well. Despite

the challenging heterogeneity of the data, the construction of a PD-Atlas with this protocol is feasible.

The contrast of the subcortical gray matter regions in PD-brains is inferior compared to controls. Data

from more patients are being processed to improve the precision and compensate for the variability

between patients.


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14:52 - 15:05 Effects of Inaccurate Identification of Interictal Epileptiform Pileptiform Discharges in Concurrent EEG-fMRI K. Gkiatis1, K. Bromis1, I. Kakkos1, I. S. Karanasiou2, G. K. Matsopoulos1, K. Garganis3 1Department of Electical and Computer Engineering, National Technical University of Athens, Greece 2Department of Mathematics and Engineering Sciences, Hellenic Military University, Athens, Greece 3Epilepsy Monitoring Unit, “St. Luke’s” Hospital, Thessaloniki, Greece

Corresponding Author: K Gkiatis, [email protected] Keywords: EEG, fMRI, Simultaneous, Concurrent, Epilepsy, Reliability Concurrent continuous EEG-fMRI is a novel multimodal technique that is finding its way into clinical

practice in epilepsy. EEG timeseries are used to identify the timing of interictal epileptiform discharges

(IEDs) which is then included in a GLM analysis in fMRI to localise the onset epileptic zone.

Nevertheless, there are still some concerns about its reliability concerning BOLD changes correlated

with IEDs. Even though IEDs are identified by an experienced neurologist-epiliptologist, the reliability

and concordance of the mark-ups is depending on many factors including the level of fatigue, the

amount of time that he spents or, in some cases, even the screen that is being used for the display of

timeseries. This investigation is aiming to unravel the effect of misidentification or inaccuracy in the

mark-ups of IEDs in the Fmri statistical parametric maps. Concurrent EEG-fMRI was conducted in six

subjects with various types of epilepsy. IEDs were identified by an experienced neurologist-

epiliptologist. Analysis of EEG was performed with EEGLAB and analysis of fMRI was conducted in FSL.

Preliminary results revealed lower statistical significance for missing events or larger period of IEDs

than the actual ones and the introduction of false positives and false negatives in statistical

parametric maps when random events were included in the GLM on top of the IEDs. Our results

suggest that mark-ups in EEG for the simultaneous EEG-fMRI should be done with caution from an

experienced and restful neurologist as it affects the fMRI results in various and unpredictive ways.

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15:05 - 15:18 Brain Functional Connectivity in Small Cell Lung Cancer Population after Chemotherapy Treatment: AN ICA fMRI Study K. Bromis1, I. Kakkos1, K. Gkiatis1, I. S. Karanasiou2, G. K. Matsopoulos1

1Department of Electrical and Computer Engineering, National Technical University of Athens, Greece 2Department of Mathematics and Engineering Sciences, Hellenic Military University, Athens, Greece

Corresponding Author: K Bromis, [email protected] Keywords: SCLC, PCI, ICA, DMN, TPN, fMRI.

Previous neurocognitive assessments in Small Cell Lung Cancer (SCLC) population, highlight the

presence of neurocognitive impairments (mainly in attention processing and executive functioning) in

this type of cancer. The majority of these studies, associate these deficits with the Prophylactic Cranial

Irradiation (PCI) that patients undergo in order to avoid brain metastasis. However, there is not much

evidence exploring cognitive impairments induced by chemotherapy in SCLC patients. For this reason,

we aimed to investigate the underlying processes that may potentially affect cognition by examining

brain functional connectivity in nineteen SCLC patients after chemotherapy treatment, while

additionally including fourteen healthy participants as control group. Independent Component

Analysis (ICA) is a functional connectivity measure aiming to unravel the temporal correlation between

brain regions, which are called brain networks. We focused on two brain networks related to the

aforementioned cognitive functions, the Default Mode Network (DMN) and the Task-Positive Network

(TPN). Permutation tests were performed between the two groups to assess the differences and

control for familywise errors in the statistical parametric maps. ICA analysis showed functional

connectivity disruptions within both of the investigated networks. These results, propose a detrimental

effect of chemotherapy on brain functioning in the SCLC population.


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15:18 - 15:30 Electroencephalographic Coherence Investigation in Psychiatric Patients Undergoing the Primitive Expression Form of Dance Therapy E. C. Ventouras1, M. Argyri1, M. Lalou1, A. Margariti2, 3, P. Chondraki2, N.-T. Economou2, H. Tsekou2,

T. Paparrigopoulos2, P. Ktonas2

1Department of Biomedical Engineering, Technological Educational Institution of Athens, Greece 2Department of Psychiatry, 1st Psychiatric Clinic, Eginition Hospital, Medical School, University of

Athens, Greece 3Department of Theater Studies, University of Peloponnese, Nafplion, Greece

Corresponding Author: E C Ventouras, [email protected] Keywords: Dance therapy (DT), Primitive expression (PE), Electroencephalography (EEG), Brain connectivity, coherence One of the earliest known forms of therapeutic experience and practice is dancing. There exist various

dance therapy (DT) methodologies, one of them being Primitive Expression (PE). PE involves an

interaction of ethologically and socially based forms that are supplied for re-enactment. Previous

research has indicated that the inclusion of neurophysiological parameter measurements, in the

protocol of dance therapy, might provide useful insights concerning brain connectivity changes in

psychiatric patients during the PE DT process. In the present study, the electroencephalographic (EEG)

recordings of a group of 8 schizophrenic patients undergoing PE DT were examined. Coherence was

computed among 6 EEG electrodes and a mean coherence value was extracted, per EEG rhythm,

namely delta (0.4-3.5 Hz), theta (4-7 Hz), alpha (8-12 Hz), low beta (13-20 Hz) and high beta (21-30 Hz)

rhythms. Acute potentiation effects on coherence, as a result of a single PE DT session, were examined.

Indication is provided that the acute potentiation effects of PE DT are more prominent in the middle of

the DT total process duration than towards the end of it. Furthermore, the majority of cases where an

acute effect was detected concerned inter-hemispheric connectivity, rather than intra-hemispheric

connectivity. Central electrodes are more involved in the acute effects. Finally, the EEG rhythm that

seemed to be most affected was the delta rhythm, while the least affected was the theta rhythm.


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16:00 - 17:45 Session 4. Biomedical Applications Session Chairpersons: I. Kalatzis, P. Asvestas

16:00 - 16:13 Automated Breast Ultrasound for Ductal Pattern Reconstruction: Ground Truth File Generation and CADe Evaluation D. Manousaki1, A. Panagiotopoulou1, V. Bizimi2, M. S. Haynes3, S. Love4, M. Kallergi1

1Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece 22nd Radiology Department, University Hospital “Attikon”, Athens, Greece 3Jet Propulsion Laboratory (JPL), Pasadena, CA, USA 4Dr. Susan Love Research Foundation, Encino, CA, USA

Corresponding Author: M Kallergi, [email protected] Keywords: Automated breast ultrasound, Breast imaging, Breast ductal pattern, CADe evaluation The purpose of this work was twofold: (a) generate ground truth files (GTFs) of the breast ducts from

images of the Invenia™ Automated Breast Ultrasound System (ABUS) system (GE Healthcare, Little

Chalfont, UK) and (b) use the generated truth files to evaluate a computer aided detection algorithm

(CADe) developed for the automated detection of the ducts by scientists at the Jet Propulsion

Laboratory (Pasadena, CA, USA).

In a pilot study for the in-vivo imaging of the breast ductal pattern, six lactating, nursing volunteers

were scanned with the ABUS by radiology technologists at Breastlink Orange (Orange, CA, USA) and

overseen by scientists from Dr. Susan Love Research Foundation (Encino, CA, USA). Mean age was 33.5

years and mean lactation time was 10.5 months; three of the women were primipara and three were

multipara. The women were imaged before and right after breastfeeding their infants. Three image

volumes were recorded for each breast, an anterior-posterior (AP) volume, a lateral (LAT), and a

medial (MED) volume. An expert in breast ultrasound generated rough outlines of the milk-filled ducts

in the AP volume slices using ImageJ. Final GTFs were generated by two trained assistants. In addition,

all image volumes were processed with a JPL CADe method. CADe results were compared to the

expert’s GTFs by estimating true positive fraction (TPF) or % overlap. Breast and duct volumes were

also estimated and compared to the literature.

Two sets of GTFs were generated per volunteer yielding a total of twelve sets; six before and six after

lactation. The process was completed in a 12-month period and required 143 person-hours. An

analysis of the results showed that the average right breast volume was 573.7 ml (SD=217.1 ml) and

average left volume was 605.3 ml (SD=241.7 ml). The detected duct volumes were small compared to

the entire breast area (≤1%) showing that only a small part of the ductal system was detectable since

only parts of some of the ducts were filled with milk and, consequently, only parts of some of the ducts

demonstrated sufficient contrast to be observed with the ABUS. Based on the pre-lactation GTFs, the

left breast showed significantly more milk-filled ducts than the right breast in 5 of the 6 volunteers

(P=0.046). Such differences were not observed post-lactation. An analysis of the upper and lower

halves of each breast showed that, in agreement with prior studies, more milk-filled ducts were

detected in the lower half than the upper half in 5 out of 6 volunteers. CADe results differed

significantly from the expert’s. TPF ranged from 0% to 39% for either the left or right breast.

The generation of GTFs for the breast ducts based on the INVENIA ABUS images of 6 lactating females

was a labor and time intensive yet necessary process. The files provide a valuable tool in the

optimization of the imaging system, the imaging protocol, and the CADe algorithms.


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16:13 - 16:26 A Disposable Flexible Moisture Sensor Directly Printed on Paper for Medical Applications D. Barmpakos1, A. Segkos2, C. Tsamis2, G. Kaltsas1

1Department of Electronic Engineering, Technological Educational Institute of Athens, Greece 2Institute of Nanoscience and Nanotechnology (INN), NCSR Demokritos, Athens, Greece

Corresponding Author: D Barmpakos, [email protected] Keywords: Inkjet – printed electronics, Paper substrate, Flexible sensor

The present study demonstrates an inkjet – printed interdigitated electrode array on paper substrate

and its evaluation as moisture sensor for medical applications. Firstly, inkjet printing principles of

operation and theoretical background have been studied. Afterwards, the utilized silver nanoparticle

ink properties have been investigated both optically, with scanning electron microscopy and optical

microscopy, and electrically with IV characteristics and resistivity calculations for different geometries.

Inkjet droplet formation analysis has been performed in order to achieve repeatable results regarding

generated droplets, based on the driving pulses applied on the inkjet piezoelectric element. Droplet

formation has been monitored using stroboscopic effect. Polyimide, polyethylene terephthalate, inkjet

transparency films and three different paper substrates, namely high glossy inkjet photo paper (basis

weight 280g/m2, thickness 11.5mil), glossy inkjet photo paper (basis weight 210g/m2, thickness 9.5mil)

and matte inkjet photo paper (basis weight 125g/m2, thickness 5.5mil) have been tested to investigate

compatibility with the ink. Ink – substrate interface optical evaluation has been carried out and

chemical sintering process examples are presented. Finally, relative humidity and moisture detection

measurements have been carried out in a controlled environment. Repeatability, material

degradation, long term response and memory effect are some of the aspects which were studied

within the frame of the present work. The proposed system provides the opportunity for novel

biomedical applications given the flexible substrate nature and the low – cost, single – step fabrication

approach.


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16:26 - 16:39 Artificial Optical Radiation, a Real Occupational Hazard of the Electromagnetic Spectrum G. A. Gourzoulidis1, C. Kappas2

1Hazardous Agents Department, OHS Directorate, Hellenic Ministry of Labor, Athens, Greece 2Department of Medical Physics, Medical School, University of Thessaly, Greece

Corresponding Author: G Gourzoulidis, [email protected] Keywords: Artificial optical radiation (AOR), Laser safety, Non-coherent optical radiation, Electromagnetic fields (EMF), Occupational health and safety (OHS)

The electromagnetic spectrum spans an enormous range from 0 up to more than 1020 Hz in the deep

ionizing region; the most significant exposures come from the occupational environment. Between the

ionizing and the non-ionizing (EMF) part of the spectrum, lies a special one covering the UV, the IR and

the visible light, called ‘Optical Radiation’ (OR). The corresponding EU occupational Directive that

deals with artificially produced OR (AOR), includes both laser and non-coherent sources, is the

2006/25/EC one.

Thorough investigation of the EMF occupational environment, concerning the corresponding Directive

2013/35/EU, has already been conducted in the last three years, resulting to rather low risk

identification. The few high exposures detected are manageable through the application of the

appropriate Occupational Health and Safety (OHS) principles. On the contrary, the recent preliminary

investigation of the AOR occupational environment showed a much more demanding field, both for

non-coherent and for laser AOR according to Dir 2006/25/EC.

Non-coherent AOR was assessed in the complicated environment of metal arc welding, reveling even

sub-second overexposures. Laser radiation assessment in cosmetology, research labs and industrial

environment, also revealed the need for increased OHS surveillance.

The overall investigation of the electromagnetic spectrum in the occupational environment revealed

that the EMF concern is not justified and that AOR poses real hazards that need to be faced

successfully.


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16:39 - 16:52 Classification of Error Related Brain Activity in an Auditory Identification Task with Conditions of Varying Complexity I. Kakkos1, K. Gkiatis1, K. Bromis1, P. Asvestas2, I. Karanasiou3, E. M. Ventouras2, G. Matsopoulos1

1Department of Electrical and Computer Engineering, National Technical University of Athens, Greece 2Department of Biomedical Engineering, Technological Educational Institution of Athens, Greece 3Department of Mathematics and Engineering Sciences, Hellenic Military University, Athens, Greece

Corresponding Author: I Kakkos, [email protected] Keywords: EEG, Error Detection and Monitoring, Classification, SVM, Feature Selection, SFS The detection of an error is the cognitive evaluation of an action outcome that is considered undesired

or mismatches an expected response. Brain activity during monitoring of correct and incorrect

responses elicits Event Related Potentials (ERPs) revealing complex cerebral responses to deviant

sensory stimuli. Development of accurate error detection systems is of great importance both

concerning practical applications and in investigating the complex neural mechanisms of decision

making. In this study, data are used from an audio identification experiment that was implemented

with two levels of complexity in order to investigate neurophysiological error processing mechanisms

in actors and observers. To examine and analyze the variations of the processing of erroneous sensory

information for each level of complexity we employ linear, radial basis function and quadratic kernel

Support Vector Machines (SVM) classifiers together with Sequential Minimal Optimization (SMO) and

Least Squares (LS) methods using characteristic ERP time-windowed features, such as the time of

occurrence and value of the minimum and maximum of the EEG time series and signal energy, as

represented by the area under the ERP curve. For dimensionality reduction and to remove redundant

features we implement a feature selection framework based on Sequential Forward Selection (SFS).

The proposed method provided high accuracy in identifying correct and incorrect responses both for

actors and for observers with mean accuracy of 93.3% and 91.3% respectively. Additionally,

computational time was reduced and the effects of the nesting problem usually occurring in SFS of

large feature sets were alleviated.


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16:52 - 17:05 A Software Platform for the Analysis of Dermatology Images M. Vlassi, V. Mavraganis, P. Asvestas


Corresponding Author: P Asvestas, [email protected] Keywords: Software platform, Dermatology imaging, Classification, Graphical user interface The purpose of this paper is to present a software platform developed in Python programming

environment that can be used for the processing and analysis of dermatology images. The platform

provides the capability for reading a file that contains a dermatology image. The platform supports

various image formats such as Windows bitmaps, JPEG, JPEG2000, portable network graphics, TIFF

etc. Furthermore, it provides suitable tools for selecting, either manually or automatically, a region of

interest (ROI) on the image. The automated selection of a ROI includes filtering for smoothing the

image and thresholding. Finally, the proposed software platform provides various algorithms such as

the Gaussian, Naive Bayes, Decision Tree, neural networks etc. These algorithms can be used for the

classification of the ROI as benign or malignant using color features, textural features and geometric

features. The classification algorithms were trained using a sufficient number of dermatology images,

including healthy moles and melanomas. The proposed software platform has a friendly and clear

graphical user interface and could be a useful second-opinion tool to a dermatologist. Furthermore, it

could be used to classify images including from other anatomical parts such as breast or lung, after

proper re-training of the classification algorithms.


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17:05 - 17:18 Monitoring, Tracking, and Recording Pancreas-Related Health Issues in Real Time T. Chrysikos1, I. Zisi1, C. Katsini2, G. Raptis2, S. Kotsopoulos1

1Electrical and Computer Engineering, University of Patras, Greece 2Human Opsis, Patra, Greece

Corresponding Author: G Raptis, [email protected] or [email protected] Keywords: E-health platform, Medical Implant Communication Service (MICS), Patients monitoring

The monitoring of pancreas-related health issues in real-time and outside the medical room is a

challenge in the wide e-health domain. This paper introduces WHEAMO, a novel e-health platform

which employs medical implants (biosensors), which function as antennas, planted in the pancreas.

WHEAMO uses wireless in-body propagation to track, monitor, and record critical parameters, such as

glucose. The signal reaches the skin and then it is propagated in an indoor environment (e.g., medical

room) over to a terminal equipped with adaptive, user-configurable, and intelligent mechanisms which

provide personalized recommendations to varying WHEAMO users (e.g., medical personnel, health

care workers, patients). The personalized nature of the provided recommendations are based on

patients’ unique characteristics via a sophisticated knowledge-base. The fundamentals of in-body and

on-body wireless propagation and channel characterization have been studied in a series of published

works. Researchers have tested both electric-field (dipole) and magnetic-field (patch, loop) antennas.

Another important aspect concerns the frequency band in which the signal propagation will occur.

Among the frequencies that have gathered scientific and academic interest are the Medical Implant

Communication Service (MICS) band at 402-405 MHz, the 900 MHz channel and the industrial,

scientific and medical (ISM) radio band at 2.45 GHz.



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17:18 - 17:30 Electronic Management of Medical Records: The Vital Role of Electronic Patient File V. Manoli

Philologist, Librarian and Information Scientist, ΜA in Sciences of Education, ΜΒΑ

Corresponding Author: V Manoli, [email protected] Keywords: Record Management System, Electronic Medical Records, Electronic Patient File, E-Health.


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17:30 – 17:43 Laser-Induced Refractive Index Modification of Intraocular Lenses C. Bacharis1, G. Tsilikas1, I. Sianoudis2, M. Makropoulou1, A. Serafetinides1

1Department of Physics, School of Applied Mathematical and Physical Sciences, National Technical

University of Athens (NTUA), Greece 2Department of Optics & Optometry, Technological Educational Institute (TEI) of Athens, Greece

Corresponding Author: C Bacharis, [email protected] Keywords: Intraocular lens, Refractive power of IOLs The purpose of this work is to modify non-invasively the refractive power of an already implanted

intraocular lens (IOL) in situ, with the appropriate laser parameters. Preliminary experimental results

on the effect of short and ultra-short laser radiation on IOL polymer refractive capacity will be

presented. We applied different pulsed laser radiation parameters, in sub-ablation threshold energy

fluence values, on commercially available hydrophobic and hydrophilic acrylic IOLs. The laser source

was a Ti:Sapphire laser at λ= 800nm, pulse width tp=48 fs, frequency=85 MHz and an Nd:YAG laser at

6 ns pulse width.

The morphology of the IOL surface and quantitative measurements of the refractive index were

examined at various settings of laser pulses, different focal length and laser fluencies. Quantitative

measurements of the refractive index were performed by measuring the IOLs power with laboratory

lensmeter and Abbe refractometer.

The experimental results of refractive power value changes show a linear behavior with laser intensity,

in the case of NIR fs laser irradiation, with a small modification (~ 0.25 D) of the refractive power at

the non-ablative laser parameters used in this work. The exact photo-induced modification of

refractivity mechanism must be further elucidated.


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Parallel Poster Session-B (10:30– 18:30) Session Chairpersons: V. Koukou, N. Matrini

1. Identification of Arteries and Veins from Cerebral Angiography

I. Tache

Dept. of Automatic Control and Systems Engineering, University Politehnica of Bucharest, Romania

Corresponding Author: Tache, [email protected] Keywords: k-means, Classification, Angiography In the present research study a new method for pixels tagging into two classes of arteries and veins

from temporal angiography is presented. This need comes from the neurosurgeon who have to

investigate the cerebral angiography and magnetic resonance images in order to give locate the

fistula of the patients who suffer from arteriovenous malformation. The fistula it’s identified at the

conjunction of the arteries and veins.

There were ten temporal image series with almost 20 images per series to process. The method

includes the elimination of the background pixels from a previous segmentation and the generation of

the time intensity curves for each remaining pixel. For these curves, some signal processing is

undergone in order to extract the characteristic parameters needed for applying the k-means

clustering. Some of the parameters are: the phase and the maximum amplitude extracted from the

Fourier transform, the standard deviation and the mean value, etc. The tagged classes are represented

into images which are then classified into images which contain artery pixels or vein pixels.

Acknowledgement

The acknowledgement is dedicated to the research staff of Inserm U703, from France for providing

me the data as long with the idea to identify the arteries and veins from the angiography.


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2. Image Processing for Biomedical Images using Fractal Analysis A. Dumitrescu, D. Popescu

Department of Automatic Control and System Engineering, University Politehnica of Bucharest,

Romania

Corresponding Author: A Dumitrescu, [email protected] Keywords: Fractal analysis, Classification, Vascular diseases

The branching patters of circulatory system have characteristics of a fractal. The fractal analysis of

biomedical images for a retinal vascular system could identify diseases with a non-invasive method. In

this paper, we study the classification of vascular diseases using images of retinal vascular system, to

which we associate corresponding fractal dimension.


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3. Infrared Thermography Quantitative Image Processing A. Skouroliakou1, I. Kalatzis2, N. Kalyvas2 , T.B. Grivas3

1Department of Energy Technology Engineering, Technological Educational Institute (TEI) of Athens,

Greece 2Department of Biomedical Engineering, Technological Educational Institute (TEI) of Athens, Greece 3Department of Orthopaedics and Traumatology, Tzaneio General Hospital of Piraeus, Greece

Corresponding Author: A Skouroliakou, [email protected] Keywords: Infrared Thermography, Image Processing

Infrared thermography is an imaging technique that has the ability to provide a map of temperature

distribution of an object’s surface. It has a wide range of applications in medicine as well as in non-

destructive testing procedures.

One of its promising medical applications is in orthopaedics and on diseases of the musculoskeletal

system where temperature distribution of the body’s surface can contribute to the diagnosis and

follow up of certain disorders. Although the thermographic image can give a fairly good visual

estimation of distribution homogeneity and temperature pattern differences between two symmetric

body parts, it is important to extract a quantitative measurement characterising temperature. Certain

approaches use temperature of certain symmetric anatomical points, or parameters extracted from a

Region of Interest. A number of indices have been developed by researchers to that end.

In this study a quantitative approach in thermographic image processing is attempted based on

extracting different indices for symmetric Regions of Interest on thermograms of the lower back area

of scoliotic patients. The indices are based on first and second order statistical parameters describing

temperature distribution and their values for the symmetric body areas are compared.


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4. Institutional Patient Doses in Multislice Computed Tomography A. Moka1, G. Messaris1, A. Hadjikonstanti1, P. Zampakis2, C. Kalogeropoulou2, G. Panayiotakis1

1Department of Medical Physics, School of Medicine, University of Patras, Greece

2Department of Radiology, School of Medicine, University of Patras, Greece

Corresponding author: G Panayiotakis, [email protected] Keywords: Computed Tomography, Institutional doses Computed Tomography (CT) is a high patient radiation dose technique. In this study, the institutional

doses for CT examinations for chest, abdomen and chest/abdomen, in the University Hospital of

Patras, are presented. The systems used were the Toshiba Aquilιon Prime (80 slices) and the General

Electric Lightspeed (16 slices). Three hundred patients participated in this study, fifty for each

examination and system. The patient characteristics (age, sex, BMI), the volumetric CT dose index

(CTDIvol) and the dose length product (DLP) were recorded. Additionally, the 75th percentile values of

the CTDIvol and DLP distributions were estimated, for comparison purposes. For Toshiba scanner the

75th percentile CTDIvol and DLP values were 3.9 mGy and 156.1 mGy·cm for the chest, 7 mGy and 314.5

mGy·cm for the abdomen, 10.9 mGy and 612.5 mGy·cm for the chest/abdomen examinations,

respectively. For GE scanner the corresponding CTDIvol and DLP values were 12 mGy and 417 mGy·cm,

14.7 and 636.2 mGy·cm, 13.1 mGy and 771.3 mGy·cm. The values for both CT scanners were lower

than the corresponding national Diagnostic Reference Level (DRL) values. The institutional doses

reported can contribute in the establishment of the local DRLs and in the further optimization of the

techniques.


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5. Measuring the Refractive Index of Intraocular Lenses Modifited by Femtosecond LASER and UV Radiation C. Bacharis1, G. Tsilikas1, M. Makropoulou1, A. Serafetinides1, I. Valais3, E. Chalkiadaki2,

G. Mitsou4, I. Sianoudis2

1Department of Physics, School of Applied Mathematical and Physical Sciences, National Technical

University of Athens (NTUA), Greece 2Department of Optics & Optometry, Technological Educational Institute (TEI) of Athens, Greece 3Department of Biomedical Engineering, Technological Educational Institute (TEI) of Athens, Greece 4Department of Department of Energy Technology Engineering, Technological Educational Institute

(TEI) of Athens, Greece

Corresponding Author: I Sianoudis, [email protected] Keywords: Intraocular lens, Refractive index measurements

The exposure of intraocular lenses to pulsed laser radiation, and alternatively to UV radiation may

potentially alter their optical characteristics with respect to those originally manufactured. The

purpose of this work is the determination of the refractive index of intraocular lenses, by applying a

series of different methods of measurements. These methods were compared and evaluated in order

to assess the suitability and reliability of the results obtained, their adoption and selection for the

determination of the refractive index of intraocular lens, to which have previously been attempted.

Measurements were performed on intraocular lens specimens, with methods and instruments

provided by our conventional optical laboratory, before and after radiation treatment, and the results

were discussed. More specifically, methods of measuring the refractive index of optical materials were

used with the aid of an Abbe refractometer, a Lenspowermeter (indirectly), by optical image

formation, the principle of determining the total reflection angle, and by means of Michelson

interferometry. Part of the effort of this work is to establish and consolidate the process that will be

selected for the study and control of a desired change in the index of refraction of intraocular lenses

after treatment using UV radiation and pulsed laser light in the area of nano- and femtosecond

radiation.


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6. Non-Invasive Spectroscopic Techniques in the Diagnosis of Non-Melanoma Skin Cancer E. Drakaki1, I. Sianoudis1, M. Makropoulou2, A. Serafetinides2, C. Dessinioti3, E. Stefanaki3, A.

Stratigos3, C. Antoniou3, A. Katsambas3, E. Christofidou3

1Dept. of Optics & Optometry, Technological Educational Institute of Athens, Greece 2School of Applied Mathematical and Physical Sciences, National Technical University of Athens,

Greece 3University of Athens, Dept. of Dermatology, Hospital A. Syggros, Athens, Greece

Corresponding author: E Drakaki, [email protected] Keywords: Spectroscopic techniques, Non-melanoma skin cancer, Diagnosis The number of non-melanoma skin cancers is increasing worldwide and has become an important

health and economic issue. Early detection and treatment of skin cancer can significantly improve

patient outcome. Therefore there is an increase in the demand for proper management and effective

noninvasive diagnostic modalities in order to avoid relapses or unnecessary treatments.

Although the gold standard of diagnosis for non-melanoma skin cancers is biopsy followed by

histopathology evaluation, optical non-invasive diagnostic tools have obtained increased attention.

Emerging non-invasive or minimal invasive techniques with possible application in the diagnosis of

non-melanoma skin cancers include high-definition optical coherence tomography, fluorescence

spectroscopy, oblique incidence diffuse reflectance spectrometry among others spectroscopic

techniques.

Our findings establish how those spectrometric techniques can be used to more rapidly and easily

diagnose skin cancer in an accurate and automated manner in the clinic.

Acknowledgement

This research effort, part of the overall project, is financially supported by the Project “Grants for

research “ARCHIMEDES III”, grant No 021215, Code MIS: 379389, “FluDiaPhoSkin Therapy” funded by

the Technological Education Institute (TEI) of Athens.

Finally we would like to thank I. Vamvakas, M. Kompitsas I. Kalatzis, L. Zekou, Ch. Evagelatos, N.

Merlemis, G. Mitsou, I. Valais, I. Karachalios, D. Mathes for their participation and contribution to this

project.


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7. Numerical Assessment of Brain Tumor Pharmacokinetics after Blood-Brain/Blood-Tumor Barrier Disruption with Focused Ultrasound Y. Guo1, M. O. Bernabeu2, C. Arvanitis1

1School of Mechanical Engineering, Department of Biomedical Engineering, Georgia Institute of

Technology, Atlanta, Georgia, USA 2Centre for Medical Informatics, Usher Institute, University of Edinburgh, Edinburgh, UK

Corresponding author: C Arvanitis, [email protected] Keywords: Drug delivery, Drug transport modelling, Brain tumors

Blood-brain and blood-tumor barriers (BBB and BTB) constitute a major obstacle to the transport of

therapeutics in brain tumors. While several studies have demonstrated the potential of focused

ultrasound (FUS) to disrupt transiently the BBB/BTB and improve drug delivery, there is a lack of

fundamental understanding of the impact of this method on the pharmacokinetics of anticancer

agents in the brain microenvironment. In this study, we examine the impact of FUS-induced BBB/BTB

disruption on the transport of two anticancer agents (doxorubicin and ado-trastuzumab emtansine -

T-DM1) in brain cancer using drug transport mathematical modeling.

We developed a convection-diffusion-reaction model of drug transport with different reaction terms

for doxorubicin and ado-trastuzumab emtansine - T-DM1 and then inferred the model parameters

(vessel permeability, porosity, etc) from experimental data using unconstrained numerical

optimization procedures. Based on the fitted values, we performed a sensitivity analysis in order to

determine the most important parameters that affect the drug transport and cellular uptake in the

tumor interstitium.

The fitted to experimental data mathematical model indicated that the vessel diffusion coefficient

and the tissue hydraulic conductivity increased significantly after FUS-BBB/BTB disruption as

compared to control for Doxorubicin. For the larger molecule T-DM1 the hydraulic conductivity

appeared to be the only parameter that increased significantly after FUS-BBB/BTB disruption.

Sensitivity analysis using the fitted values showed that FUS-BBB/BTB disruption eliminates the

sensitivity to vessel diffusion coefficient in the FUS-treated animals, suggesting that FUS is able to

overcome one of the major obstacles to the transport of small molecule anticancer agents

(Doxorubicin) in brain tumors. For both agents the cellular internalization appears to be the major

determinant in drug transport in brain tumor microenvironment and strategies to modify it may lead

to improved uptake.

The proposed framework provides a systematic way to identify novel ultrasound-nanomedicine

combinations for optimal intratumoral penetration.


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8. Performance Evaluation of Two DR Radiography Systems and Patient Dose in Chest Examination J. Antonakos, J. Kagkiouzis, P. Tsionopoulou, C. Basiliou, E. Efstathopoulos

2nd Department of Radiology, University of Athens, Greece

Corresponding Author: J Antonakos, [email protected] Keywords: Digital Radiology, Detective Quantum Efficiency

The performance of two radiography systems equipped with flat panel detectors (FPD) in terms of

physical parameters such as modulation transfer function (MTF), normalized noise power spectrum

(NNPS), detective quantum efficiency (DQE), signal to noise ratio (SNR) and entrance surface air kerma

(ESAK) , under conditions intended in chest radiography.

A Fuji and a Cannon FPD, parts of a PHILIPS and a GE radiography units respectively, were utilized for

MTF, NNPS and DQE measurements according to IEC 62220-1 standard and ImageJ software. ESAK

estimated from measurements on a patient equivalent phantom (PEP) at chest radiography

conditions. The overall performance evaluated in terms of FOM measurements.

NNPS, MTF and DQE of Fuji FPD had better performance than Cannon’s at the whole range of

frequencies. ESAK on PEP phantom at chest radiography settings was measured 0,07mGy and 0.26

mGy at Philips and GE units respectively. SNR calculated 0.89 at Philips and 0.58 at GE and FOM of the

systems was 35 and 0.26 respectively.

The comparative performance of two radiographic systems in clinical practice is the result of many

factors such as the detection system and the performance of the tube and the generator.


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9. Polymer Based Thin Film Screen Preparation Technique I. Valais1, C. Michail1, C. Fountzoula2, G. Fountos1, G. Saatsakis3, A. Karabotsos4, G.S. Panayiotakis3,

I. Kandarakis1

1Department of Biomedical Engineering, Technological Educational Institute (T.E.I.) of Athens,

Greece 2Department of Medical Laboratories, Technological Educational Institute (T.E.I.) of Athens, Greece 3Department of Medical Physics, Medical School, University of Patras, Greece 4Department of Conservation of Antiquities and Works of Art, Technological Educational Institute

(T.E.I.) of Athens, Greece

Corresponding Author: I Valais, [email protected] Keywords: Polymers, PMMA, film screens

Phosphor screens, mainly prepared by electrophoresis, demonstrate brightness equal to the standard

sedimentation on glass or quartz substrate process and are capable of very high resolution.

Nevertheless, they are very fragile, the shape of the screen is limited to the substrate shape and in

order to achieve adequate surface density for application in medical imaging, a significant quantity of

the material will be lost. Polymethyl methacrylate (PMMA) is widely used as a plastic optical fiber, it

shows almost nearly no dispersion effects and it is transparent in the whole visible spectral range.

Fluorescent films can be prepared by the dispersion of inorganic nanoparticles into an organic

transparent thermoplastic polymer, such as PMMA.

The aim of this study is to enhance the stability of phosphor screens preparation method via the

incorporation of phosphor particles into a polymer matrix, such as PMMA. Different concentrations of

PMMA in MMA were examined and a 28% w /w solution was used for the preparation of the thin

polymer film, since optical quality characteristics were found to depend on PMMA in MMA

concentration. Scanning Electron Microscopy Images of the polymer screens demonstrated high

packing density and uniform distribution of the phosphor particles.

This method could be potentially used for phosphor screen preparation of any size and shape.


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10. Pulse Shape Estimation of Nuclear Medicine Photodetectors using a Bi-Exponential Fitting Model E. Fysikopoulos1, Y. Kopsinis2, M. Georgiou1, G. Loudos1

1Department of Biomedical Engineering, Technological Educational Institution of Athens, Greece

2Department of Informatics and Telecommunications, University of Athens, Greece

Corresponding Author: E Fysikopoulos, [email protected] Keywords: Digital Pulse Processing, Field Programmable Gate Arrays, Data acquisition, Levenberg-Marquardt algorithm, Position Sensitive Photomultiplier Tube, Silicon Photomultiplier, Single Photon Emission Computed Tomography State of the art data acquisition systems for small animal imaging gamma ray detectors often rely on

free running Analog to Digital Converters (ADCs) and high density Field Programmable Gate Arrays

(FPGA) devices for digital signal processing. In this work, a sub-sampling acquisition approach, which

exploits a priori information regarding the shape of the obtained detector pulses is proposed. Output

pulses shape depends on the response of the scintillation crystal, photodetector’s properties and

amplifier/shaper operation. Using these known characteristics of the detector pulses prior to

digitization, one can model the voltage pulse derived from the shaper), in order to reduce the desirable

sampling rate of ADCs. Fitting with a small number of measurements, pulse shape estimation is then

feasible. In particular, the proposed sub-sampling acquisition approach relies on a bi-exponential

modeling of the pulse shape. We show that the properties of the pulse that are relevant for Single

Photon Emission Computed Tomography (SPECT) event detection (i.e. position and energy) can be

calculated by collecting just a small fraction of the number of samples usually collected in data

acquisition systems used so far. Compared to the standard digitization process, the proposed sub-

sampling approach allows the use of free running ADCs with sampling rate reduced by a factor of 5.

Acknowledgment

This research has been funded by IKY Fellowships of excellence for postgraduate studies in Greece –

Siemens Program.


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11. Resolution Properties of a Calcium Tungstate (CaWO4) Thin Screen Coupled to a CMOS Imaging Detector V. Koukou1, N. Martini1, I. Valais2, A. Bakas3, N. Kalyvas2, G. Fountos2, I. Kandarakis2, C. Michail2

1Department of Medical Physics, Medical School, University of Patras, Greece 2Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of

Biomedical Engineering, Technological Educational Institute of Athens, Greece 3Department of Radiology & Radiation Therapy, Technological Educational Institute of Athens, Greece

Corresponding Author: C Michail, [email protected] Keywords: CaWO4, Medical imaging, CMOS, MTF

The aim of the current work was to assess the resolution properties of a thin calcium tungstate

(CaWO4) screen (screen coating thickness: 36.26 mg/cm2, actual thickness: 118.9 μm) coupled to a

high resolution complementary metal oxide semiconductor (CMOS) digital imaging sensor. A

2.7x3.6cm2 CaWO4 sample was extracted from an Agfa Curix universal screen and was coupled directly

with the active area of the active pixel sensor (APS) CMOS sensor. Experiments were performed

following the new IEC 62220-1-1:2015 International Standard, using an RQA-5 beam quality.

Resolution was assessed in terms of the Modulation Transfer Function (MTF), using the slanted-edge

method. The CaWO4/CMOS detector configuration was found with linear response, in the exposure

range under investigation. The final MTF was obtained through averaging the oversampled edge

spread function (ESF), using a custom-made software developed by our team, according to the IEC

62220-1-1:2015. Considering the renewed interest in calcium tungstate for various applications, along

with the resolution results of this work, CaWO4 could be also considered for use in X-ray imaging

devices such as charged-coupled devices (CCD) and CMOS.


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12. Spatial Resolution of Lu2O3:Eu Thin Screens Coupled to a High Resolution CMOS Imaging System I. Seferis1, 2, J. Zeler2, C. Michail3, I. Valais3, G. Fountos3, N. Kalyvas3, A. Bakas4, I. Kandarakis3, E.

Zych2, G. S. Panayiotakis1

1Department of Medical Physics, Medical School, University of Patras, Greece 2Faculty of Chemistry, University of Wroclaw, 50-383 Wroclaw, Poland 3Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of

Biomedical Engineering, Technological Educational Institute of Athens, Greece 4Department of Radiology & Radiation Therapy, Technological Educational Institute of Athens, Greece

Corresponding Author: G Panayiotakis, [email protected] Keywords: Lu2O3:Eu, CMOS , X-ray imaging

The influence of the grain shape and size on spatial resolution (ranging from nano to micro scale) of

various Lu2O3:Eu phosphor screens was investigated. All screens were prepared using the

sedimentation method. Three screens were prepared with spherical grains and sizes 50 nm, 200 nm

and 5 μm, whilst two screens with rod-like shape grains and sizes 500 nm and 1-8 μm. All screens were

coupled to a high resolution CMOS digital imaging sensor (Remote RadEye HR) consisting of 1200 x

1600 pixels with 22.5 μm pixel pitch. Experiments were performed under radiographic conditions,

using 70 kVp tube voltage and 63 mAs tube load. Spatial resolution was assessed utilizing the

Modulation Transfer Function (MTF). It was found that the influence of the grains shape on imaging

performance was more crucial than the grain size. The rod-like grains showed very poor spatial

resolution. The influence of grains size between 50 nm 200 nm and 5 μm was negligible on MTF

values.


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13. Spectroscopic Measurements and Estimation of Dangers by the Protection of Sun Radiation with Sunglasses I. Sianoudis1, G. Mitsou2

, I. Valais3

1Department of Optics & Optometry, Technological Educational Institute (TEI) of Athens, Greece 2Department of Department of Energy Technology Engineering, TEI of Athens, Greece 3Department of Department of Biomedical Engineering, TEI of Athens, Greece

Corresponding Author: I Sianoudis, [email protected] Keywords: Sun radiation, Absorption/reflectance/transmission measurement, Optical spectroscopy, UV eye protection

Significant changes in vision, frequent injuries, illnesses and fast early aging are recorded due to

incomplete or ineffective eye protection from solar radiation. The spectral distribution of radiation, its

intensity and, above all, the ultraviolet as well as the infrared component to a lesser extent are risk

factors for the eye, as long as it is exposed for a long time, with short and long lasting consequences.

In this work, we investigate the qualitative and quantitative factors in order to assess the impact, to

compare the obtained values with the guidelines of health organizations that have instituted and the

technical specifications of the products. For this purpose, spectroscopic measurements have been

made on all optical characteristics of the protective materials and means, such as sunglasses, by

checking the effectiveness of the protection they provide and the satisfaction of the corresponding

specifications under the regulations and directives that have been legally enacted.


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14. Study of the Dopamine Effect into Cell Solutions by Impedance Analysis G. Paivana1, T. Apostolou1, G. Kaltsas2, S. Kintzios1

1Department of Biotechnology, Agricultural University of Athens, Greece 2Department of Electronic Engineering, Technological Educational Institute of Athens, Greece

Corresponding Author: G Paivana, [email protected] Keywords: Impedance analysis, Dopamine, Immobilization method, N2a cells

Electrochemical Impedance Spectroscopy (EIS) has become a technique that is frequently used for

biological assays. Impedance is defined as a complex – valued generalization of resistance and varies

depending on its use per application field. In health sciences, bioimpedance is widely used as

noninvasive and low cost alternative in many medical areas that provides valuable information about

health status. This work focuses on assessing the effects of a bioactive substance applied to

immobilized cells. Dopamine was used as a stimulant in order to implement impedance analysis with a

specific type of cells. Dopamine constitutes one of the most important catecholamine

neurotransmitters in both the mammalian central and peripheral nervous systems. The main purpose

is to extract calibration curves at different frequencies with known dopamine concentrations in order

to describe the behavior of dopamine, cells and also the mix of these two solutions using an

impedance measurement device. For comparison purposes, the corresponding measurements were

evaluated for non-immobilized cells in the measurement cells.


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15. The Effect of X-ray Irradiation on Intraocular Lens Implants S. Ellas1, J. Antonakos1, K. Platoni1, C. Bacharis2, M. Makropoulou2, A. Serafetinides2, E.

Efstathopoulos1

12nd Department of Radiology, Medical School, National and kapodistrian University of Athens, Greece 2Physics Department, Faculty of Applied Mathematical and Physical Sciences, National Technical

University of Athens, Greece

Corresponding Author: E Efstathopoulos, [email protected] Keywords: Intraocular lenses, X-ray irradiation, Transmission, UV-blue light protection filter

Intraocular lens (IOLs) implants are synthetic lenses used to replace the natural lens of the eye and

obtain optical rehabilitation in cataract surgery. However, postoperative complications such as

capsular opacification, considerable cloudiness or discoloration appear 2-3 years after the surgery.

Factors affecting postoperative "life" of the IOL according to the international literature have not yet

been fully clarified. The implantation of intraocular lenses increased extremely in our days, with a

tendency to enter also in other ophthalmology disorders. Thus, the monitoring of eye exposures to

patients, physicians, and radiation workers which have IOL implants has become of increased interest.

In this study we examine the effect of x-ray irradiation at clinical doses in radiodiagnosis and

radiotherapy of human eye on the IOL implants. We examine any effect on the transmittance and UV-

blue light protection of the modern yellow azo-dye doped IOLs. Our findings demonstrate that the

irradiation with x-rays decreases the filter protection of the yellow azo-dye doped IOLs against the

harmful for the retina UV radiation and short wavelength blue right.


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16. The Examination of the Binder on the Optical Performance of Phosphor Materials Used in Medical Imaging Systems G. Kleideri, P. Liaparinos


Corresponding Author: P Liaparinos, [email protected] Keywords: Binder, Phosphor materials, X-ray detectors

The light emission performance of powder phosphors, employed in indirect X-ray detective systems, is

affected by their structural (i.e., the particle size and packing) and optical properties (i.e., the

wavelength of the light rays and the refractive index of the grains). In the chemical synthesis and the

corresponding construction development of phosphor layers, the binder plays crucial role though its

contribution to the way that the grains are glued together in a packed spatial distribution. In this

study, the binder was examined for the widely used Gd2O2S:Tb powder material (light wavelength: 545

nm, refractive index: 2.3, grain diameter: 7 μm, packing density: 50 %) considering phosphor layer of

200 μm. Different binders were considered by changing the values of the refractive index (from 1.1 up

to 1.8). The optical diffusion (i.e., the light photon interactions with the phosphor grains) was

examined by Monte Carlo (MC) simulation models. Mie scattering theory was used to feed the

required data for the MC models. Results showed that binders of high refractive index correspond to

more transparent phosphor layers (i.e., light emission increase) with considerably low decrease of their

spatial resolution.


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17. The Formation of Chimeric Nanomorphologies, as a Reflection of Naturally Occurring Thermodynamic Processes N. Naziris1, N. Pippa1, 2, V. Chrysostomou2, S. Pispas2, C. Demetzos1, M. Libera3, B. Trzebicka3

1Section of Pharmaceutical Technology, Department of Pharmacy, School of Health Sciences, National

and Kapodistrian University of Athens, Greece 2Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens, Greece 3Centre of Polymer and Carbon Materials, Polish Academy of Sciences, Zabrze, Poland

Corresponding Author: C Demetzos, [email protected] Keywords: Chimeric liposomal systems, Divergent self-assembly, Membrane morphology, Disorder biophysics The self-assembly process of different in nature biomaterials leads to the morphogenesis of various

nano-structures, where the individual molecule properties (e.g. hydrophilic-to-hydrophobic balance

and elasticity), profoundly affect the intermediate surfaces’ interfacial thermodynamics. Herein, the

mixing of a phospholipid and an amphiphilic block copolymer, through the thin-film hydration method,

gave different morphologies, among which there were vesicles (i.e. liposomes and polymersomes),

micelles and worm-like structures. The formation of such variety of structures is attributed to

divergent entropic pathways, which are determined by a number of parameters, such as the

lipid:polymer molar ratio and the polymer composition. The developed nanosystems are considered as

chimeric/mixed, because of the two different in type biomaterials that compose them. The vesicles

also exhibited membrane “irregularities”, which are connected with their biophysical behavior. Nature

has “chosen” vesicular forms to be the thermodynamically stable “biological apartments”, in which life

was enclosed and additionally, vesicles provided compartmentalized systems, where the intracellular

environment was built. Phospholipid properties result in membranes/bilayers that harmonically

assimilate other molecules, like proteins and retain their integrity and functionality, while gaining

additional features. A cause that alters this relationship might induce changes in the membrane

composition and morphology, with respect to lipid rafts/domains, what has been linked with the

activation and development of certain human disorders/diseases. The self-assembly of two different

biomaterials into various structures that present distinct membrane phenomena is believed to

simulate these natural processes.


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18. The Role of Particle Packing of Powder Phosphor-Based X-ray Detectors through Monte Carlo Simulation Techniques P. Liaparinos1, N. Kalyvas1, E. Katsiotis1, I. Kandarakis1

1Radiation Physics, Materials Technology and Biomedical Engineering, Department of Biomedical

Engineering, Technological Educational Institute of Athens, Greece

Corresponding Author: P Liaparinos, [email protected] Keywords: Powder phosphors, Packing density, Monte Carlo

In medical imaging, the quality of the medical image is directly connected to the imaging performance

of phosphor-based X-ray detector. Several conventional powder phosphors have been due to their

physical and optical properties, however, the particle packing effects of powder phosphor material

within a radiation detector requires further examination. The present work attempted to examine and

evaluate the significance of using different particle packing on a phosphor layer. The model was

performed by using Mie scattering theory and Monte Carlo simulation techniques and it was carried

out by taking into packing density from 10 % up to 90 % within two different phosphor layers, 100 μm

(thin layer) and 200 μm (thick layer), respectively. The light emission performance was assessed

through the amount and distribution of light at the output surface of the phosphor layer considering

three values of phosphor grain diameter 100 nm, 500 nm, and 1 μm. The most significant outcome of

the present investigation was that improved spatial resolution can be achieved without significant

decrease in light collection efficiency, if particles in the submicrometer scale with relatively low

packing density are used.

Acknowledgement




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19. The Role of Surgeon on Patient Dose During Fluoroscopically Guided Lumbar Discectomy and Fusion V. Metaxas1, G. Messaris1, G. Gatzounis2, F. Tzortzidis2, D. Konstantinou2, G. Panayiotakis1

1Department of Medical Physics, School of Medicine, University of Patras, Greece 2Department of Neurosurgery, School of Medicine, University of Patras, Greece

Corresponding Author: G Panayiotakis, [email protected] Keywords: Lumbar discectomy and fusion, Fluoroscopy, Patient dose, Surgeon

In this study, the role of surgeon on patients' radiation dose, during fluoroscopically guided lumbar

discectomy and fusion, was evaluated. Fluoroscopy time (FT), kerma area product (KAP) and

cumulative dose (CD) were recorded for 96 patients who underwent single or multilevel procedures

with a C-arm fluoroscopy system (Philips BV Endura), that were divided into three groups, based on

the surgeon performed each procedure. Entrance surface dose (ESD) and effective dose (ED) were

estimated utilizing appropriate conversion coefficients, based on FT and KAP values, respectively. The

mean FT, KAP, CD, ESD and ED values were 21.5s, 0.77Gy·cm2, 3.51mGy, 18.3mGy, 0.09mSv for the

first, 23.0s, 1.44Gy·cm2, 6.52mGy, 19.5mGy, 0.18mSv for the second, and 14.2s, 0.64Gy·cm2, 2.91mGy,

12.1mGy, 0.08mSv for the third surgeon, respectively. The differences in dose values were not

statistically significant, although the p-values were close to the threshold of statistical significance.

The third surgeon achieved the lowest dose values. Although the first surgeon achieved almost the

same FT with the second surgeon, the corresponding dose values were decreased about 50%. These

can be attributed to the better implementation of the fluoroscopy system technical parameters, with

respect to the clinical conditions and complexity of each procedure. Training and awareness of

neurosurgeons on radiation protection issues is of critical importance, in order to further optimize such

procedures, in terms of both patient and staff doses.


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20. The Use of Scanning Microscopy and X-ray Energy Dispersion Analysis to Evaluate Orodispersible Tablets

B. Sarecka-Hujar1, R. Balwierz2, A. Ostróżka-Cieślik1, R. Dyja1, D. Lukowiec3, A. Jankowski1

1Medical University of Silesia in Katowice, School of Pharmacy with the Division of Laboratory

Medicine in Sosnowiec, Department of Pharmaceutical Technology, Sosnowiec, Poland 2Silesian Medical College in Katowice, Poland 3Silesian University of Technology, Department of Materials Processing Technology, Management and

Computer Techniques in Materials, Gliwice, Poland

Corresponding Author: B S Hujar, [email protected] Keywords: Scanning microscopy, EDS analysis, Energy dispersion, Tablets The quality of the drug, its purity and identification of degradation products ensure the highest quality

of pharmaceutical products. The energy dispersed spectroscopy (EDS) method analyzes the percentage

of each element in the tablet as well as their distribution, and morphological characteristics of the

drug form. We performed assessment of usefulness of EDS method for testing orally disintegrating

tablets (ODT). We used high resolution, above 25 scanning electron microscopy (SEM, SUPRA25 Carl

Zeiss Company) with spectrophotometer equipped with an X-ray energy dispersion (EDAX Company).

The samples of the analyzed tablets were imaged after applying conductive layers of gold on the

surface. In the EDS analysis the composition of each sample of the tablets was observed to be virtually

identical. The differences in the content of carbon and oxygen arise from differences in the

composition of particular tablets. The presence of gold in the composition results from the sputtering

with gold on the surface of the sample, the silicon and magnesium – from talc and chlorine – from the

active substance. Knowing the composition of the tablet, SEM-EDS method help to locate and identify

the impurities and degradation products of the compounds, leading to a better understanding of the

mechanisms of their formation.


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21. The Utility of the Drug-To-Lipid Ratio at the Optimization of the Liposomal Formulation

M. Chountoulesi1, N. Naziris1, N. Pippa1, C. Demetzos1

1Section of Pharmaceutical Technology, Department of Pharmacy, School of Health Sciences, National


Corresponding Author: C Demetzos, [email protected]

Keywords: Drug-to-lipid ratio, Liposomal formulation, Therapeutic efficacy, Regulation

Liposomes are considered to be one of the most extensively investigated drug delivery nanosystems.

Many liposomal products have already been marketed approved. However, the development of a

liposomal product is a complicated process, because many critical parameters are involved during the

process and therefore all these parameters have to be investigated. Τhis study deals with the drug-to-

lipid ratio (D/L ratio), which is a critical process parameter, expresses the actual capacity of the

liposome to accommodate the drug and can play a key role at the optimization of every liposomal

formulation. More specifically, D/L ratio is strongly affected by the composition of the liposomal

product, the different biomaterials, their structural and physicochemical characteristics, as well as the

drug loading method and the whole preparation process being used. Furthermore, D/L ratio influences

the therapeutic efficacy of the liposomal product, expressing the actual dose of the drug being

administrated and regulating also the drug release. Moreover, there is a variety of analytical methods,

quantifying the drug and the lipids, estimating therefore the D/L ratio. In conclusion, the regulatory

framework of nanomedicine, enlists D/L ratio in the necessary elements needed for the nanosimilar

product description during the statement of product comparability, confirming its significance.


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22. Thermo-Responsive Drug Nanocarriers based on Novel PNIPAM-b-POEGA Amphiphilic Block Copolymers D. Giaouzi1, S. Pispas2


Corresponding Author: D Giaouzi, [email protected] Keywords: Amphiphilic block copolymers, Thermo-responsive nanocarriers, Drug delivery Over the past decades, amphiphilic block copolymers have attracted the scientific interest because of

their ability to self-assemble in aqueous solutions. Stimuli-responsive, amphiphilic block copolymers

present great interest as far as synthesis, self –assembly in aqueous solutions and drug delivery

applications are concerned. Poly(N-isopropylacrylamide) (PNIPAM) is a thermoresponsive polymer

which displays a lower critical solution temperature(LCST) of 32 OC, close to human body temperature

(~37oC) which make it pretty attractive for drug delivery applications. In the present work, well-defined

poly(N-isopropylacrylamide)-b-poly (oligo ethylene glycol methyl ether acrylate) (PNIPAM-b-POEGA)

block copolymers were successfully synthesized via RAFT polymerization. The copolymers were utilized

as smart nanocarries for the nonsteroidal anti-inflammatory hydrophobic drug indomethacin

implementing a novel encapsulation protocol taking advantage of the thermoresponsive behavior of

the PNIPAM block, which becomes considerably hydrophobic at temperatures close to body

temperature. The empty and loaded self-assembled nanocarriers systems were studied by a gamut of

physicochemical techniques, including static, dymanic and electrophoretic light scattering (SLS, DLS,

ELS), UV-Vis and FTIR spectroscopy, which gave information on the size and structure of the

nanocarriers, the drug loading content and the interactions between the drug and the components of

the block copolymers.


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23. Towards the Experimental Assessment of the DQE in SPECT Scanners G. Fountos, C. Michail

Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of

Biomedical Engineering, Technological Educational Institute of Athens, Greece

Corresponding author: G Fountos, [email protected] Keywords: SPECT, DQE, MTF, NNPS, LSF, Film, Flood source

The purpose of this work was to introduce the Detective Quantum Efficiency (DQE) in single photon

emission computed tomography (SPECT) systems using a flood. A Tc-99m-based flood source (Eγ=140

keV) consisting of a radiopharmaceutical solution of dithiothreitol (DTT, 10-3 M)/Tc-99m(III)-DMSA, 40

mCi/40 ml bound to the grains of an Agfa MammoRay HDR Medical X-ray film) was prepared in

laboratory. The source was placed between two PMMA blocks and images were obtained by using the

brain tomographic acquisition protocol (DatScan-brain) and the myocardial perfusion tomographic

acquisition protocol (Tc-99m-MIBI-heart). The Modulation Transfer Function (MTF) was evaluated for

various reconstruction methods and filters. All imaging experiments were performed in a Siemens e-

Cam gamma camera. The Normalized Noise Power spectra (NNPS) were obtained from the sagittal

views of the source. Higher MTF values were obtained for the brain scan protocol with Iterative 3D

with 8 iterations reconstruction method. MTF of the brain protocol was in all cases better than the

heart protocol. The noise levels of the SPECT reconstructed images, in terms of the NNPS, were found

to increase as the number of iterations increase. The behavior of the DQE was influenced by both MTF

and NNPS. As the number of iterations was increased, higher MTF values were obtained, however

with a parallel, increase of magnitude in image noise, as depicted from the NNPS results. The method

presented here is novel and easy to implement, requiring materials commonly found in clinical

practice and can be useful in the quality control of SPECT scanners.


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24. Initial Evaluation of New Radiochromic Micelle 3D Dosimeter Formulations K. Kouvati1, K. Kwiatos2, L. Petrokokkinos3, M. Jaszczak2, P. Papagiannis1, M. Kozicki2

1Medical Physics Laboratory, Athens Medical School, National and Kapodistrian University of Athens,

Greece 2Department of Man-Made Fibres, Lodz University of Technology 3Physics Department, National and Kapodistrian University of Athens, Greece

Corresponding Author: K Kouvati, [email protected] Keywords: Dosimetry, Radiochromic gels, Spectrophotometry

Radiochromic dye gels are used in conjunction with optical computed tomography for 3D dosimetry

purposes.

In the current work three dye precursors (Leuco-crystal violet -LCV-, Leuco-malachite green -LMG- and

2,3,5-triphenyltetrazolium chloride -TTC-) were examined in new gel formulations in terms of dose

response sensitivity, dose rate dependence and temporal stability using medical ionizing radiation

beams (X-Ray tube and LINAC in Flattening-Filter-Free mode). Pluronic F-127 was used as a gelling

agent due to its favourable characteristics (micellization with increasing temperature, optical clarity).

Spectrophotometric measurements were performed pre- and post-irradiation at the wavelength of

maximum absorbance for each recipe.

All formulations were found dose rate independent from 70 to 1110 Gy/min. The LCV and TTC

folrulations were rather stable for a period of 24 h pre- and 65 h post-irradiation, relative to just 2 h

pre- and 6 h post-irradiation for the LMG formulation. Results indicate a linear dose response with a

sensitivity of 0.0015, 0.001 and 0.0005 Gy-1cm-1 for the LCV, LMG and TTC formulations, respectively.

The corresponding intercepts (an indirect measure of optical clarity) were found equal to 0.0435,

0.0461 and 0.1095 cm-1, for the LCV, LMG and TTC formulations, respectively.

Acknowledgement

Supported in part by an Erasmus+ traineeship programme supported by the European Union.


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