Monte Carlo Simulation for the ECAT EXACT HR+ system using GATE

GATE (Geant4 Application for Tomographic Emission) is a Monte Carlo simulation platform for nuclear medicine imaging, based on the Geant4 toolkit package. In order to improve data analysis and image quantification, a new simulator for the ECAT EXACT HR+ scanner was originally developed with GATE. In this study, we validate GATE simulations for positron emission topography (PET) imaging systems: a good agreement is obtained between simulated and actual experimental results. Additional GATE applications are also presented in the paper: an implementation of the voxelized Hoffman phantom and an example of a MRI/PET coupling system for improving image resolution.