A modified statistical system model and an accelerated Monte Carlo simulation for a silicon detector based Compton medical imaging system

The objective of this research is to demonstrate a modified statistical system model and an approach of accelerated Monte Carlo simulation for studying the capability of a dual-planar Compton medical imaging system constructed with silicon and NaI detectors to image 364.4 keV energy photons emitted from I131. The Compton imaging system is a potential medical imaging instrument for effectively observing the process of radionuclide cancer treatments. Since decoupling the tradeoff between spatial resolution and detection efficiency inherent to the absorbing collimation of conventional Anger Camera, the Compton imaging system provides improved imaging performance in both detection efficiency and spatial resolution especially for higher energy photons. In the study, a modified statistical system model of the Compton system was developed considering all factors in the Compton process including Doppler broadening, energy resolution and spatial resolution of the scattering and absorbed detectors in addition to the Compton image formation process. To conquer the limitation of low simulation speed when employing the existent allpurpose Monte Carlo simulation platform due to low Compton interaction cross-section inside of the silicon detector, the developed Monte Carlo simulation involves the techniques of force detection and variance reduction to speed up the simulation. It is proved that two promotion approaches are of benefit to performance analysis and image reconstruction for the Compton imaging system.