Modeling of 3D gamma interaction position in a monolithic scintillator block with a row-column summing readout

Current positron emission tomography (PET) systems have their detector design based on discrete scintillation crystals. Spatial resolution of these systems are directly related with the size of the crystal segments. On the other hand, cost and complexity increase considerably as the size of the crystal segments decreases. Detector design with continuous scintillator is another approach that improves the energy resolution and sensitivity without degrading the spatial resolution. In this work, we report a method to determine the gamma interaction position with depth of interaction (DOI) capability inside a monolithic crystal coupled to a photodetector array. The method is based on estimating parameters of a model which describes the signal distribution of the optical photons collected by the photodetector array in a row-column summing readout scheme. Evaluation data were simulated using the GATE framework (Geant4 Application for Emission Tomography) to characterize the detector and to compare the interaction position of the incident gamma with the position registered by the detector.