Comparison of a GATE Monte Carlo simulation predictions to the performance of a high-resolution LYSO based dedicated animal PET camera

A Monte Carlo simulation of the performance of a high-sensitivity and high-resolution small animal positron emission tomography (PET) scanner with a large axial field-of-view (AFOV) is presented and compared to the measured data. The simulated camera is based on the photomultiplier-quadrant-sharing (PQS) concept and composed of 180 blocks of 13×13 lutetium-yttrium oxyorthosilicate (LYSO) crystals with an average crystal size of 1.24 mm transaxially, 1.4 mm axially, and 9.5 mm radially. The camera has 78 detector rings with an 11.6 cm AFOV and a ring diameter of 16.6 cm. For the simulation, we used the Geant4 Application for Tomographic Emission (GATE) simulation package. We first validated GATE by comparing its predictions for spatial resolution, absolute sensitivity, and count rate with measured data obtained using an existing bismuth germanate (BGO) based dedicated animal PET scanner that had a similar AFOV and ring diameter and was also based on the PQS technique. Simulated and experimental images of the Data Spectrum Micro Deluxe phantom were also compared.