Development of a dual-sided readout DOI-PET detector using 500-μm-pitch 64-ch SiPMs

Abstract

Positron emission tomography (PET) is a nuclear imaging technique that can visualize molecular-level biological processes and is widely used in cancer examinations. The current spatial resolution of small-animal PET systems is sub-millimeter level.In addition, the pixel size of the detector and parallax error are important factors that affect the spatial resolution of a PET imaging system. In this study, to develop a high-resolution small-animal depth-of-interaction (DOI) PET detector, we used a novel 500-μm-pitch silicon photomultipliers (SiPMs), as developed by UTokyo and KETEK, that has a recovery time of 8 ns and gain of 1 × 106. To realize DOI estimation, two SiPMs were used to detect the scintillation light from both ends of a Ce:Gd3Al2Ga3O12 (GAGG) scintillator (00.4 mm × 0.4 mm × 2 mm). The experimental results show that a good DOI resolution of less than 3 mm can be achieved. The simulation results show that, for a detector with 3-mm DOI resolution, the spatial resolution was approximately 0.28 mm at the center of the field of view, and 0.63 mm at 20 mm from the center.