A GATE Monte Carlo Simulation of the Performance of a High-Sensitivity and High-Resolution LSO Based Small Animal PET Camera

A Monte Carlo simulation of the performance of a high-sensitivity and high-resolution small animal PET scanner with large axial field-of-view (AFOV) is presented. The simulated camera is based on the photomultiplier-quadrant-sharing technique and composed of 180 blocks of 14 times 14 LSO crystals (each crystal is 1.16 times 1.27 times 10 mm³). The designed camera consists of 84 detector rings with an AFOV of 11.6 cm and ring diameter of 16.6 cm. For simulation, we used GATE (Geant4 Application for Tomographic Emission) simulation package. GATE is a GEANT4 based software toolkit for realistic simulation of PET and SPECT systems. In this study, we first validated GATE by comparing its prediction for spatial resolution, absolute sensitivity, NEC, and images of the Data Spectrum Micro Deluxe phantom with the measured data using an existing BGO small animal PET scanner which is also based on the photomultiplier-quadrant-sharing technique and has similar AFOV and ring diameter. Spatial resolution simulation was done for point sources located at the center of the camera and also off the center. Simulation data suggest that new LSO scanner could have a reconstructed radial (tangential) spatial resolution of 1.14 (1.14) mm, 1.31 (1.32) mm, 1.54 (1.52) mm, 2.01 (1.8) mm at the center, and 1 cm, 2 cm and 3 cm off the center, respectively. It predicts that 1.2 mm hot rod inserts in the Micro Deluxe phantom will be distinguishable. Simulation predicts an absolute sensitivity of about 6.