Evaluation of 3D Monte Carlo-Based Scatter Correction for 99m Tc Cardiac Perfusion SPECT

Cardiac SPECT images are degraded by photons scattered in the thorax. Accurate correction for scatter is complicated by the non-uniform density and varied sizes of thoraxes and by the additional attenuation and scatter caused by female patients ’ breasts. Monte Carlo simulation is a general and accurate method for de-tailed modeling of scatter. Hence, for 99mTc we compared statis-tical reconstruction based on Monte Carlo modeling of scatter with statistical reconstruction that incorporates the more com-monly used triple-energy-window scatter correction. Both of these scatter correction methods were used in conjunction with attenuation correction and resolution recovery. Methods: Simul-taneous attenuation, detector response, and Monte Carlo–based scatter correction were implemented via the dual-matrix ordered-subset expectation maximization algorithm with a Monte Carlo simulator as part of the forward projector (ADS-MC). ADS-M