Development of continuous detectors for a high resolution animal PET system

We propose a design for high resolution, gamma camera style detectors suitable for use in a positron emission tomograph dedicated to small animal research. Through calculation and Monte Carlo simulation we model the performance of a detector comprised of a 76.2×76.2×8 mm thick LSO crystal coupled to a 3" square position sensitive photomultiplier tube (PS-PMT). We investigated the effect of optical coupling compounds, surface treatment and depth of interaction on the quantity (efficiency) and distribution (spread) of scintillation photons reaching the photocathode. We also investigated linearization of the position response and describe an algorithm for determining the loss in system spatial resolution due to depth of interaction effects. We propose a PET system consisting of fourteen of these detectors in 2 rings, yielding a 16 cm Ø by 15 cm long tomograph. It would operate in 3-D mode subtending a 68% solid angle to the center. The expected spatial resolution is ⩽2 mm, with a system efficiency of ~10% (200 keV lower threshold) and a singles count rate capability of 8×10⁶ cps per detector