Slat collimation and cylindrical detectors for PET simulations using SimSET

SimSET (a Simulation System for Emission Tomography) is a public domain simulation of PET and SPECT. The recently released version 2.6 adds capabilities to simulate slat collimation for dual-headed coincidence imaging (DHCl) and cylindrical detectors for positron emission tomography (PET). The slat collimator module simulates axial slats of attenuating material in front of planar detectors. The collimator may be composed of multiple materials and be radially layered. The cylindrical detector module simulates an annulus of detector material. The detector may also be composed of multiple materials, and may vary axially and radially, but transaxial cuts are not simulated. Validation tests compared results from slat collimator and cylindrical detector simulations to analytic predictions and to simulations using other previously tested SimSET modules. Beta testers have used both modules extensively.