Validation of the SPECT features of a simulation system for emission tomography

SimSET (a Simulation System for Emission Tomography) is a widely used simulation package in the nuclear medicine research community. In this paper we present validation measurements for the SPECT-related modules of the package. Decay generation and tracking through the object were checked for correct distribution of starting angle and weight, and correct proportion and spatial distribution of unscattered, Compton and Rayleigh scattered photons. We tested that the collimator module, which models the collimator using geometric transfer functions, implements the underlying equations and positions the collimator correctly. The binning of detected photons into histograms was checked for accuracy. Finally, a comparison of simulated data and experimental data is given.