A TECHNIQUE FOR SIMULATION OF THE POINT-SPREAD FUNCTION OF A GAMMA-CAMERA

A technique for simulating the point spread function (PSF) Of gamma-camera images which treats primary photons and detected scattered photons separately is described. The primary photon PSF Was measured at different distances in air from the camera. The scatter PSF was also assessed with different thicknesses of water between the point and the camera, and fitted to a circularly symmetric bi-exponential function. An analysis of the variation of detected scattered radiation based on the results is presented. Simulation of the PSF at a given distance from the camera and thickness of attenuating medium was then possible from the sum of the appropriate primary photon PSF corrected for attenuation and the appropriate scatter PSF. The accuracy of the technique has been studied with variation in depth, density and uniformity of thickness of the attenuating medium.