A 3-D Monte Carlo simulation of a small animal Positron Emission Tomograph with millimeter spatial resolution

We have used the EGS4 Monte Carlo code to simulate the performance of a Positron Emission Tomograph for small animals. The tomograph is a four-head detector, made of matrices of 400 YAP:Ce finger-like crystals (2x2x30 mm(3) each) coupled to Position Sensitive Photo-Multipliers Hamamatsu R2486-06. 3-D reconstruction algorithms have been applied to the 3-D simulated data. The reconstructed volume was 2x2x2 cm(3), the same of the reference mouse brain. The Monte Carlo results show that a spatial resolution below 2 mm (EWHM) can be obtained over the 2x2x2 cm3 volume with a sensitivity of about 600 counts/(mu Ci.s) for a gantry diameter of 15 cm, and a threshold of 50 keV.