Performance of a PET Detector Based on Multi-resolution SiPM Array

High-resolution positron emission tomography (PET) detectors often have crystal array pitches smaller than the photodetector array pitch, making it difficult to resolve the edge crystals due to limited light sharing. In this paper, we proposed a multi-resolution SiPM array design to better resolve the edge crystals. This design uses a mix of SiPMs with different sizes and arranges smaller SiPMs around larger SiPMs. A pseudo 9 × 9 multi-resolution SiPM array, consisting of 6.47 × 6.47 mm
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SiPMs, 6.47 × 3.07 mm
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, and 3.07 × 3.07 mm
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SiPMs, was implemented on a 16 × 16 array of MicroFJ-30035 SiPMs with a pitch size of 3.4 mm. Similarly, an 8 × 8 SiPM array with a pitch size of 6.8 mm was mimicked by merging 2 × 2 groups. The flood histograms and energy resolution of detectors based on these three SiPM arrays were compared using a 36 × 36 lutetium yttrium orthosilicate (LYSO) array with a pitch of 1.5 mm and a thickness of 10 mm. The results show that the flood histogram obtained using the 16 × 16 SiPM array is the best, and the flood histogram obtained using the 9 x 9 multi-resolution SiPM array is much better than that obtained using the 8 × 8 SiPM array. The energy resolutions obtained using the three SiPM arrays are similar, and around 10%.