Silicon photomultipliers (SiPMs) are now widely used for positron emission tomography (PET) applications because of their high gain and low noise characteristics. The PET image quality has been improved with the advancement of time-of-flight (TOF) and depth-of-interaction (DOI) measurement techniques. For brain-dedicated PET systems, both TOF and DOI information are beneficial for enhancing the reconstructed PET image quality. In a previous study, we proposed SiPM-based dual-ended readout PET detectors that used a mean time method to achieve coincidence timing resolution (CTR) of 349 ps and DOI resolution of 2.9 mm. However, the coincidence timing resolution (CTR) was worse than 300 ps since the crystal surface and the reflector type were not optimized. This study aimed at investigating the optimal crystal surface treatment and the reflector material to achieve a sub-200 ps CTR and sub-3 mm DOI resolution with a dual-ended readout PET detector using an LYSO crystal (2.9נ2.9נ20 mm³). The scintillation light inside the LYSO crystal was read out by two SiPMs using the dual-ended readout method. The CTR and DOI resolution were measured with two different crystal surfaces (polished and saw-cut) and three different reflector material scenarios of ESR without grease (i.e., air coupling), ESR with optical grease and Teflon. We digitized the timing and energy signals by using a V775N TDC module (35 ps bit⁻¹) and V965 QDC module, respectively. The combination of the saw-cut LYSO crystal and the ESR with air coupling resulted in the best CTR (18832 ps) and DOI resolution (2.90.2 mm) with the dual-ended readout configuration. We concluded the dual-ended readout method in combination with the saw-cut crystal and the ESR reflector with air coupling can provide a sub-200 ps CTR and sub-3.0 mm DOI resolution simultaneously.

硅光电倍增管 (SiPM) 现在广泛用于正电子发射断层扫描 (PET) 应用，因为它们具有高增益和低噪声特性。随着飞行时间 (TOF) 和相互作用深度 (DOI) 测量技术的进步，PET 图像质量得到了提高。对于大脑专用 PET 系统，TOF 和 DOI 信息都有利于增强重建的 PET 图像质量。在之前的一项研究中，我们提出了基于 SiPM 的双端读出 PET 检测器，该检测器使用平均时间方法实现 349 ps 的重合时间分辨率 (CTR) 和 2.9 mm 的 DOI 分辨率。然而，由于晶体表面和反射器类型没有优化，重合时间分辨率 (CTR) 低于 300 ps。³）。LYSO 晶体内的闪烁光由两个 SiPM 使用双端读出方法读出。CTR 和 DOI 分辨率是用两种不同的晶体表面（抛光和锯切）和三种不同的反射器材料场景测量的，ESR 没有油脂（即空气耦合），ESR 使用光学油脂和聚四氟乙烯。我们使用 V775N TDC 模块（35 ps bit ^-1) 和 V965 QDC 模块。锯切 LYSO 晶体和带有空气耦合的 ESR 的组合使用双端读出配置产生了最佳的 CTR (18832 ps) 和 DOI 分辨率 (2.90.2 mm)。我们得出结论，双端读出方法结合锯切晶体和带空气耦合的 ESR 反射器可以同时提供低于 200 ps 的 CTR 和低于 3.0 mm 的 DOI 分辨率。