Monte Carlo modeling of scintillator crystal performance for stratified PET detectors with DETECT2000

In order to determine the theoretical performance of the multilayer BGO scintillation block used in small positron emission tomography (PET) scanners, we have used the DETECT2000 Monte Carlo simulation of the light transport in scintillation crystal software. The scintillation block is made of two arrays of individual crystals and they are held together by an interconnecting layer. The results given by this software demonstrate that some of the individual crystals in the block could not be distinguished even under the best circumstances. Also, we have found that it would be difficult to correctly distinguish an important fraction of the individual crystals under bad conditions. The simulations determined that the layer connecting the different crystals is the most important factor of degradation of the performance of the scintillation block. Simulations of different widths of interconnecting layer suggest that much better identification could be obtained by reducing the width of this layer.