Improved coordinate reconstruction for SiPM based gamma detector with pixelated scintillating crystal and multiplexed readout

Currently the prevailing high-resolution Positron Emission Tomography (PET) detector architecture consist of a high-density and high-atomic number scintillating crystals coupled to a pixelated photosensitive layer such as position sensitive photomultiplier tubes (PS-PMTs) or silicon photomultiplier (SiPM) arrays. Such detectors typically rely on some form of analog signal multiplexing in order to minimize the number of readout electronics channels and the positions of the gamma ray interactions are calculated using Center-of-Gravity (CoG) method.In this paper we report on the Truncated Center of Gravity (TCoG) and Raised To the Power (RTP) methods for reconstruction of the positions of the gamma ray interactions as applied to a newly developed small-scale PET detector prototype based on 24x24 LYSO scintillation crystal arrays and 8x8 SiPM arrays. In the current small-scale prototype, the analog signal readout is optimized with 64:16 multiplexing ratio.A notable advantage of using TCoG or RTP algorithms instead of basic Centre-of-Gravity (CoG) is demonstrated. Particularly, the Field of View (FOV) distortion inherent to CoG reconstruction is eliminated.