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 of W.R. Nelson et al. (1985) to simulate the performance of a positron emission tomograph (PET) for small animals. The PET scanner is a four-head detector, made of matrices of 400 YAP:Ce (yttrium aluminium perovskite doped with cerium) finger-like crystals (2×2×30 mm3 each), coupled to Hamamatsu R2486-06 position-sensitive photomultipliers. 3D reconstruction algorithms have been applied to the 3D simulated data. The reconstructed volume was 2×2×2 cm3, the same as that of the reference mouse brain. The Monte Carlo results show that a spatial resolution below 2 mm (FWHM) can be obtained over the 2×2×2 cm3 volume with a sensitivity of about 600 counts/(μCis) for a gantry diameter of 15 cm and a threshold of 50 ke