@misc{oai:repo.qst.go.jp:00083623,
 author = {Kang, Hangyu and Kang, Hangyu},
 month = {Oct},
 note = {Positron emission tomography (PET) scanners have evolved to provide good coincidence timing resolution (CTR) to enhance the reconstructed PET image quality by using time-of-flight (TOF) information. For clinical TOF-PET detectors using 20 mm long crystals, the choice of reflector materials is important as the light collection efficiency (LCE) and CTR are affected by the reflector materials. The aim of this study is to investigate the effects of reflector materials on the CTR and energy resolution of a TOF-PET detector using a 20 mm long fast-LGSO crystal. Two different surface conditions, mechanical polishing (M.P) and chemical polishing (C.P), were investigated. Each polished crystal had the same dimensions of 3.0 × 3.0 × 20 mm3 which are suitable for one-to-one coupling with an SiPM. The effects of reflector materials on the CTR and energy resolution were evaluated for ESR (65 μm thick), Lumirror (70 μm thick) and Teflon tape (100 μm thick). Each polished scintillation crystal was optically coupled to a 3.0 mm × 3.0 mm SiPM (Hamamatsu, S13360-3050CS, Japan) to build a TOF detector. A high-frequency SiPM readout circuit was used to extract the timing and energy information. A Na-22 source was used to irradiate 511 keV annihilation photons onto the TOF detector. For the fast-LGSO with M.P, ESR showed the best CTR (177±2 ps) and energy resolution (9.1%) compared to Lumirror (182±2 ps, 10.0%) and 2 layers of Teflon (179±2 ps, 10.2%) because of the uniform LCE along the crystal depth. For the fast-LGSO with C.P, ESR also had the best CTR (181±1 ps) and energy resolution (9.9%) compared to the other reflectors. In conclusion, ESR would be the best choice among the evaluated reflectors for clinical TOF-PET detectors using the fast-LGSO crystal., 2021 Virtual IEEE Nuclear Science Symposium and Medical Imaging Conference},
 title = {Effects of Reflector Materials on the CTR of a TOF-PET Detector with Fast-LGSO Crystal},
 year = {2021}
}