Monte Carlo simulation of high count rate scintillation camera imaging

High activities i.e. photon fluence rates affect the image quality and activity quantitation by introducing misspositioning, pileup and count losses in the system. Monte Carlo simulations can effectively be used to evaluate these effects. Simulated energy spectra are in good agreement with measured data The scatter in the photopeak image have been separated into components and results show a significant increase in scatter-to-total ratio when pulse-tail pileup rejection is applied. The count rate effect on scatter obtained from three multiple-window methods have been compared with true scatter in the photopeak window. Results show that deviation in predicted scatter occur at high count rates. More work needs to be done to in detail model the pileup effects in the scintillation cameras