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/spl times/2/spl times/30 mm/sup 3/ 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/spl times/2/spl times/2 cm/sup 3/, 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/spl times/2/spl times/2 cm/sup 3/ volume with a sensitivity of about 600 counts/(/spl mu/Cis) for a gantry diameter of 15 cm and a threshold of 50 keV.