Performance of two depth-encoding dual-ended readout PET detectors based on SiPM arrays with the same pitch size and different active areas

Abstract

Performances of two depth-encoding positron emission tomography (PET) detectors with dual-ended readout based on silicon photomultiplier (SiPM) arrays with the same pitch size but different active areas were compared. The pitch sizes of the SiPM arrays were both 4.2 mm. One detector was based on 8 × 8 arrays of MicroFJ-30035 SiPMs, and the other one was based on 8 × 8 arrays of MicroFJ-40035 SiPMs. A 20 × 20 array of 1.42 × 1.42 × 20 mm3 polished lutetium-yttrium oxyorthosilicate (LYSO) elements was used to construct the detectors. The pitch size of the LYSO array was 1.5 mm and barium sulfate (BaSO4) with a thickness of 80 μm was used as reflector. The results showed that the detector based on the MicroFJ-40035 SiPMs provided better performance due to the larger active area. At the optimal bias voltage of 29.0 V for flood histogram and a temperature of 22.8̂C, the detector based on the MicroFJ-30035 SiPMs had a flood histogram quality of 3.84 ± 0.17, energy resolution of 12.7 ± 1.9%, signal-to-noise ratio of 102.6 ± 11.6, DOI resolution of 2.22 ± 0.51 mm and timing resolution of 978.3 ± 102.3 ps, and the detector based on the MicroFJ-40035 SiPMs had a flood histogram quality of 4.40 ± 0.25, energy resolution of 10.9 ± 1.5%, signal-to-noise ratio of 119.4 ± 10.5, DOI resolution of 2.01 ± 0.35 mm and timing resolution of 815.7 ± 86.4 ps.