A Novel Preclinical PET Scanner Constructed with Stacks of Sliced Monolithic Scintillator Rings

Conventional preclinical PET systems usually consist of discrete scintillator arrays. The spatial resolution of the system is determined by the minimum size that the crystal can be processed. Based on our previous study on monolithic scintillator ring (MSR), we proposed a second-generation sliced MSR system, with a channel reduction readout circuit consisting of 25 2×4 SiPM arrays. This work is expected to solve the edge-effect problem while achieving high spatial resolution. By conducting single crystal strip and detector experiment, we drew the following conclusions: (1) Channel reduction method was successfully applied. (2) The light distribution read from the outer surface was successfully obtained. (3) The travelling distance of photons in the circumferential direction is about 12.64 mm, similar to that of the first-generation MSR systems. (4) The propagation of photons along the height direction is limited by the ring width.The propagation of photons in the circumferential direction determines the circumferential resolution, and that of height direction determines the height resolution. Detector experiment shows that the height decoding need to be improved to clearly resolve all 12 slices. Our next step is to optimize the SiPM assembly and insert light guide between the SiPM and crystal to improve the detector decoding performance.