Physics and Radiobiology of Nuclear Medicine

(b) A photopeak is due to only photoelectric effect of g-rays, or due to all g-rays that deposit full energy in the detector. Tr ...

A radioactive sample has two g-ray photons of 130- and 120-keV ener- gies. If a NaI(Tl) crystal has an energy resolution of 10% ...

9 Gamma Cameras 108 The principles of nuclear medicine studies are based on the assessment of radionuclidic distribution in diff ...

Gamma Cameras 109 Fig. 9.1. A schematic electronics diagram of a gamma camera. CRT, cathode ray tube; PHA, pulse-height analyzer ...

mounted on a stand. The head can be moved up or down and rotated with electrical switches to position it in the field of view on ...

Collimator In gamma cameras, a collimator is attached to the face of the NaI(Tl) detec- tor to limit the field of view so that g ...

Parallel-hole collimators are classified as high-resolution, all-purpose, and high-sensitivity type, or low-energy, medium-energ ...

resenting four directional signals,X+,X−,Y+, and Y−. The capacitance values are assigned in direct proportion to the location of ...

(9.3) wherek is a constant andk/Z is the amplifier gain. TheX andY pulses are then projected on a CRT to depict the X,Y coordina ...

display of images. The computer manipulation of image contrast on LCD monitors provides a better view of images leading to more ...

cameras provide excellent intrinsic linearity and hence superior spatial resolution in image formation. Solid-State Digital Came ...

A pulse-height analyzer: (a) Reduces the background. True or false? (b) Rejects g-rays that undergo Compton scattering in the p ...

10 Performance Parameters of Gamma Cameras 118 The quality and detail of an image obtained by gamma cameras are affected by seve ...

from the photocathode and dynodes in the photomultiplier (PM) tubes have significant effects on the intrinsic resolution. In gam ...

the collimator material (e.g., lead), andt is the length or thickness of the collimator hole. This corrects for the penetration ...

monly used collimators, the most preferable photon energy being 150 keV. At energies below ~50 keV, photons are absorbed in the ...

Evaluation of Spatial Resolution Bar Phantom Qualitative evaluation of the spatial resolution of an imaging device can be made b ...

ent photon energies, flood sources of radiations of respective energies should be used. The image of the bar phantom obtained is ...

Line-Spread Function An improved method of estimating spatial resolution of a gamma camera is based on the use of a line-spread ...

Modulation Transfer Function A more complete and quantitative assessment of spatial resolution of imaging devices is made by usi ...