Performance of Dual-Ended Readout PET Detectors Based on SiPMs with Different Microcell Sizes

Silicon photomultipliers (SiPMs) are widely used in positron emission tomography (PET) and are currently available ideal photodetectors for dual-ended readout PET detectors. The parameters of SiPM affect the performance of the PET detectors. In this study, dual-ended readout detectors based on two types of latest SiPMs with different microcell sizes (KETEK PM3350-WB with 50 μm microcells and PM3325-WB with 25 μm microcells) were evaluated using 8 × 8 SiPM arrays coupled to both ends of a 23 × 23 LYSO array with a pitch size of 1.07 mm and a length of 20 mm. The pitch sizes of the SiPM arrays are all 3.36 mm. The flood histograms show that all crystals in the LYSO array can be clearly identified, whilst a better flood histogram was obtained using the PM3350-WB SiPMs. The flood histogram quality, signal-to-noise ratio (SNR), energy resolution, depth-of-interaction (DOI) resolution and timing resolution of the detector based on the PM3350-WB SiPMs were 3.19 ± 0.55, 103.96 ± 13.82, 24.65 ± 6.67 %, 1.93 ± 0.14 mm and 903 ± 125 ps, respectively, whilst these obtained using the detector based on PA3325-WB SiPMs were 2.72 ± 0.54, 87.11 ± 11.38, 23.94 ± 6.79 %, 2.03 ± 0.12 mm and 903 ± 140 ps, respectively.