Medical Imaging:Medical Imaging:the Glass Patientthe Glass Patient

Prof.dr.ir. Bart M. ter Haar RomenyProf.dr.ir. Bart M. ter Haar RomenyTechnische Universiteit EindhovenTechnische Universiteit Eindhoven

Dept. of Biomedical EngineeringDept. of Biomedical Engineering

Image Acquisition TechniquesImage Acquisition Techniques

Classical X-RayClassical X-Ray

Computed TomographyComputed Tomography

Nuclear MedicineNuclear Medicine

UltrasoundUltrasound

Magnetic Resonance ImagingMagnetic Resonance Imaging

28 December 1895

Prof. Röntgen presentinghis invention at Würzburg,

23 January 1896

The first X-ray ever:the hand of Röntgen’s wife,end 1895.

One of the firstmedical examples:a shot of hailin a hand, 1896

Anodeconnection

+ kV

Filamentconnection

High Voltagesupply

+-

Principle of the X-ray tube:

The kinetic energy of the electrons is released by the collisionat the anode. The tube is vacuum.

vacuum

Tungsten anodecathode

X-rays output

Classical X-ray imagesClassical X-ray images

Fluoroscopy with the image intensifier during angioplasty:Real-time visualization of catheters and vessels.

Imageintensifier

X-raytube

High voltagegenerator

DSA = Digital Subtraction Angiography DSA = Digital Subtraction Angiography = Röntgen X-ray with contrast in vessels= Röntgen X-ray with contrast in vessels

Dotter procedure:

Blow up balloon in obstructed vessel

Tomoscan AV Tomoscan AV EasyVisionEasyVision

CT = Computed Tomography = CT = Computed Tomography = Röntgen X-ray slices Röntgen X-ray slices 3D 3D

Greek = to cut, to slice

CT: CT: solve for 512x512 pixels by 512x512 equationssolve for 512x512 pixels by 512x512 equations

Result: Result: a slicea slice

Examples CTExamples CT

3D visualization3D visualization

Simulation of the physicsof light reflection(ray casting/tracing)

“2.5D” image

Nuclear MedicineNuclear Medicine

Principle:Principle: Instable radioactive isotopes are Instable radioactive isotopes are

made, and build in a pharmaconmade, and build in a pharmacon Patient gets contrast medium Patient gets contrast medium

injected, which injected, which specificallyspecifically stores stores in tissuein tissue

Signal position is measured with a Signal position is measured with a gamma-cameragamma-camera

IoniIonizing radiationzing radiation: GAMMA: GAMMA

When the nucleus gets too large, the “strong force” is not strong When the nucleus gets too large, the “strong force” is not strong enough to compensate the repulsive force of the protonsenough to compensate the repulsive force of the protons

AlphaAlpha radiation: He nuclei radiation: He nuclei (come only microns far in tissue)(come only microns far in tissue) BetaBeta radiation: electrons radiation: electrons (come only cm far in tissue)(come only cm far in tissue) GammaGamma radiation: high energy photons (easily go through tissue) radiation: high energy photons (easily go through tissue)

GAMMA photon(s)

Nuclear Imaging Nuclear Imaging CameraCamera

3-rotating-head SPECT scanner

SPECT =SinglePhotonEmissionComputedTomography

PET = Positron Emission TomographyPET = Positron Emission Tomography

No task During task

Positron = anti-electronWhen it meets an electron → annihilation (explosion)Two photons go in opposite direction, ring coincidence detector

Molecular ImagingMolecular Imaging

Nano-vesicles: - antibody bindings - 90.000 Gadolinium atoms - container for pharmaca - break by US shockwave - less side effects - chemotherapy on target

Highly specific tracer biomolecules

UltrasoundUltrasound

Kretz Medicor 530D

F0 F1

skin

vessel

(red) bloodcells

FFdd = F = F00 - F - F1 1 == 2 x V x cos

cc

V

FFd d = Doppler (‘difference’) frequency= Doppler (‘difference’) frequency

transducer

Doppler

3D ultrasound

Magnetic Resonance Imaging (MRI)Magnetic Resonance Imaging (MRI)

X

Y

Z ( )

Receiver Coil

Philips Medical Systems

1000 x 1000 pixels =1 million measurements

Superconducting MagnetSuperconducting Magnet

MR AngiographyMR Angiography• Excitation only of a thin slice• Non excited blood flows in the slice• Readout of little ‘zero-signal’ areas• For all slices → angiogram

Why so many imaging modalities?Why so many imaging modalities?

Choice modalityChoice modality: Tissues have different : Tissues have different properties for different physical properties for different physical interactionsinteractions

ContrastContrast: Tissue types differ in one or : Tissue types differ in one or more of these propertiesmore of these properties

Anatomical imagingAnatomical imaging versus versus functional functional imagingimaging

CT

MR

Anna Vilanova, Vienna TU / TUE - BMT

Univ. of Dusseldorf

Philips Medical Systems

A new 3D technique:

Virtual endoscopy

New Eyes are assisting the Radiologist

The overwhelming amount of data calls for condensed presentation and analysis

Philips Medical SystemsVital ImagesGroeller - TU Vienna

Image Guided SurgeryImage Guided Surgery

Bev Doolittle: The forest has eyes

Physics everywhere

• Image Acquisition• Pattern recognition

• Computer aided diagnosis

• Biomedical research• New researchers

• Strong benefit forthe patient