Physics of Imaging Systems (ROE, CT, MRI) - uni … of Imaging Systems (ROE, CT, MRI) ... (UK, 1933...

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RUPRECHT-KARLS-UNIVERSITY HEIDELBERG

Computer Assisted Clinical MedicineProf. Dr. Lothar Schad

12/9/2008 |

Physics of

Imaging Systems (ROE, CT, MRI)

Prof. Dr. Lothar Schad

Chair in Computer Assisted Clinical MedicineFaculty of Medicine Mannheim University of HeidelbergTheodor-Kutzer-Ufer 1-3D-68167 Mannheim, GermanyLothar.Schad@MedMa.Uni-Heidelberg.dewww.ma.uni-heidelberg.de/inst/cbtm/ckm/

Master‘s Program in Medical Physics



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Introduction

Introduction



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Nobel Prize is awarded for MRI technologylandmark achievement transformed healthcare in 20th century

Paul Lauterbur(1929 - 2007)

Sir Peter Mansfield(1933 - )

Nobel Prize 2003

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1901 W. C. Röntgen (Germany, 1845 - 1923) discovery of X-rays

2003 Paul C. Lauterbur (USA, 1929 - 2007) Peter Mansfield (UK, 1933 - ) development of magnetic resonance imaging (MRI)

1991 Richard R. Ernst (CH, 1933 - ) development of high resolution magnetic resonance spectroscopy (MRS)

1952 Felix Bloch (USA, 1905 - 1983) Edward M. Purcell (USA, 1912 - 1997) development of a new precision method of nuclear magnetism (NMR)

1979 Allan M. Cormack (USA, 1924 - 1998) Godfrey N. Hounsfield (UK, 1919 - ) development of Computer-Tomography (CT)

Diagnostic Imaging: Milestones



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“The Making of a Science”

source: ECR Newsletter 1/2003

Diagnostic Imaging: Pioneers

ROE

CT MRI

PET

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Why do we need imaging systems ?

„Addiction“ to image information ?

Motivation

source: Siemens “100 Jahre Röntgen” 1995



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- information recording of all sense organs from our surroundings: ≈ 109 bit/s

→ selection and filtering 1:10 million !

CNSsee

hear

smell

taste

108 bit/s

5×104 bit/s

102 bit/s

10 bit/sflowing capacity to short-term storage: 16 bit/s is recognized by the human awareness

information flow

source: Drischel. „Einführung in die Biokybernetik“, Akademie-Verlag 1972

self-aware data processing: 100 bit/sshort-term storage: 10 bit/slong-term storage: 1 bit/s

Information Flow of Sense Organs

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Imaging Systems are supporting the most effective

and powerful sensor !

Conclusion



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Fuchs and Sox. Health Affairs - Sept/Oct 2001

Physicians´ Ranking of Innovations 2001

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object (human, animal, plant, ...)

radiation source(s)

externalX-rays (Röntgen)ultrasound (US)radiofrequency (NMR)

internalradioactive tracers(PET, SPECT)

detector(s)

externalfilm (Röntgen)piezo-crystal (US)RF-coil (NMR)

internalRF-coil

source: http://bio.physik.uni-würzburg.de/public/medphys

Diagnostic Imaging: Principal



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To look into the object without cutting or destroying (non-invasively) !

Goal

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definition:

• interaction of energy with biological tissue in order to get spatially resolved information about the physical properties of the underlying biological structure

• energy has to penetrate through the body for interaction (absorption, scattering, …)

interpretation of imaging information:

• importance of measured physical properties with respect to differentiate between normal and diseased tissue (pathology)

• not fully understood

Diagnostic Imaging: Definition



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different energies means different interaction with tissue

PET and MRI are at the end of the spectrum

ionizing non-ionizing

HzHz

Micro-Visible Infrared Milli-

meter waveand RF

THz gap

10 15Hz 10 14 Hz 10 13 10 12 10 11Hz 10 10Hz

Ultra-violet

10 16 Hz10 17Hz

magneticresonance

imagingMRI

nuclear medicine / PET

10 18Hz10 19Hz

X-ray / CTimaging

100keV 10keV

terahertz pulseimaging (TPI)

NIRF

Frequency

TV satellitedish

THz Gap

OCT

X-ray

Diagnostic Imaging: Electromagnetic Wave

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12/9/2008 | Page 15Electromagnetic Wave Penetration



12/9/2008 | Page 16Bildgebende Verfahren

without ionizingradiation

with ionizingradiation

Nuclear MagneticResonance

Ultrasound X-rays Nuclear MedicalTechniques

spectroscopy(MRS)

tomography(MRI)

tomography(CT)

planar planar emissiontomography

(PET)

Diagnostic Imaging: Overview

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image by courtesy of Helmut Newton


Diagnostic Imaging: Anatomy



12/9/2008 | Page 18Diagnostic Imaging: Pathology

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12/9/2008 | Page 19Diagnostic Imaging: Animals



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The brain shows a large, left posterior / temporal / parietal metastasis. In the transaxial views, a hyper-metabolic area, measuring 2.2 x 2.1 cm with a solid center, is seen, surrounded by edema (arrow on fused image details hypermetabolic area).

PET / CT

PET / MRI

Set-up of the McPET system inside the 1.5 T clinical scanner. McPET’s ring of detectors is placed inside the MRI coil (white arrow) and transmits its output to the MC-PMTs, enclosed in the RF-shielded box in the foreground, via doubleclad optical fibers (black arrow).

A pair of PET (a) and MR (b) images contemporaneously obtained from the C-phantom at 1.5 T.

source: GE Medical Systems Farahani et al. JMR 1999

Diagnostic Imaging: System Combination- anatomic / metabolic imaging

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Biomedical Imaging



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• diagnostic

• therapy-planning and -monitoring

• screening

• monitoring of interventions

main focus of diagnostic imaging

Diagnostic Imaging: Field of Application

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X-Ray CT MR US

imaging of bone soft tissue vessel function volume

+ + + – / + + + – –

+ + +

– + + –

+ +

+

+ + + + + + + +

– + +

++ +

real-time

*

+

+

+ +

psychological stress physical stress invasiv

small high no

medium

high no

high small

no

small small

no

costs (EUR)

ca. 40

ca. 100

ca. 400

ca. 10

Diagnostic Imaging: Properties

Physics of Imaging Systems (ROE, CT, MRI) - uni … of Imaging Systems (ROE, CT, MRI) ... (UK, 1933...

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Transcript of Physics of Imaging Systems (ROE, CT, MRI) - uni … of Imaging Systems (ROE, CT, MRI) ... (UK, 1933...