Collimator Design Using Ray-Tracing Techniques

A new computer program, RAYTRC, has been written to analyze and design collimators for high-energy gamma-ray cameras used in nuclear medicine. The program finds collimator sensitivity, and geometric and penetration point source response functions. The results of this program are presented for a number of commercial collimators and for a new experimental design used to image with 511 keV gamma-rays. Collimators designed for such high-energy gamma-rays often produce bothersome hole pattern in the images due to thick septa. In order to analyze this problem we introduce a 'generalized collimator transfer function' which characterizes not only the averaged collimator response, but also the effect of hole pattern on the images.