Validation of LYSO Scintillators Coupled to SensL C-Series SiPM's Detectors

Simulation and experimental procedures, using Na-22 sources, were carried out in order to examine the spatial resolution of a preclinical positron emission tomography/magnetic resonance imaging (PET/MRI) system, due to the innovative use of Silicon Photomultiplier (SiPM) detectors coupled with doubled jaw layer lutetium yttrium oxyorthosilicate (LYSO) crystals. Optical properties of LYSO scintillation crystals were examined, and the optimal crystal configuration was determined. Noise-equivalent count rate curves were analyzed in order to determine the stability of the PET system. The highest resolution in the 511-keV photopeak was measured as 10.84% for 27.5 V, and in the 1274-keV photopeak, the best resolution was recorded as 12.75% again for 27.5 V. Moreover, simulation and experimental images of the SiPM, for 1.2-mm and 1.68-mm pixel pitch size, were compared, showing that for 27.5 V of bias voltage, the spatial resolution is better, while the gain and the noise is low. However, for 29 V, the gain is better, but there is more noise.