DMice-a depth-of-interaction detector design for PET scanners

We have previously reported on a depth-of-interaction (DOI) detector design that uses light sharing and a single-ended readout scheme. The approach depends on the modification of light transmission between paired crystals to produce a DOI effect when the ratio of the light emitted by the paired crystals was measured. A limitation of the design was the method used to control the light sharing-making production of detector modules a complicated and time consuming task. We report here on the use of laser cut reflector sheets placed between paired crystals as an efficient method to construct such modules. Simulations of 4×4 and 1×1 mm cross section crystals were performed. The simulation results indicate that a triangular reflector shape between the crystals and an air-gap reflector design around the crystals provides the best performance. The optimal length of the reflector (% length of crystal) is a function of the crystal cross section and varies between 100% for a 4×4×30 mm crystal pair to 73% for a 1×1×30 mm crystal pair. Initial experimental validation of the simulations is being done with hand cut reflector patterns with 4×4×30 mm crystals. The work will then progress to using laser cut patterns laminated between slabs of crystals, which are then cut into crystal pairs for mounting on PMTs.