Abstract：
Objective. A crosshair light sharing (CLS) PET detector as a TOF-DOI PET detector with high spatial resolution has been developed. To extend that work, a detector calibration method was developed to achieve both higher coincidence resolving time (CRT) and DOI resolution.Approach. The CLS PET detector uses a three-layer reflective material in a two-dimensional crystal array to form a loop structure within a pair of crystals, enabling a CRT of about 300 ps and acquisition of DOI from multi-pixel photon counter (MPPC) output ratios. The crystals were 1.45 × 1.45 × 15 mm3fast LGSO, and the crystal array was optically coupled to an MPPC array. It is important to reduce as many inter-crystal scattering (ICS) events as possible in advance for the accurate detector calibration. DOI information is also expected to improve the CRT because it can estimate the time delay due to the detection depth of crystals.Main results. Using crystal identification and light collection rate of the highest MPPC output reduces the number of ICS events, and CRT is improved by 26%. In addition, CRT is further improved by 13% with a linear correction of time delay as a function of energy. The DOI is ideally estimated from the output ratio of only the MPPC pairs optically coupled to the interacted crystals, which is highly accurate, but the error is large due to light leakage in actual use. The previous method, which also utilizes light leakage to calculate the output ratio, is less accurate, but the error can be reduced. Using the average of the two methods, it is possible to improve the DOI resolution by 12% while maintaining the smaller error.Significance. By applying the developed calibration method, the CLS PET detector achieves the CRT of 251 ps and the DOI resolution of 3.3 mm.
摘要：
目的：已经开发了一种十字准线光共享（CLS）PET检测器，作为具有高空间分辨率的TOF-DOIPET检测器。为了扩大这项工作，开发了一种检测器校准方法，以实现更高的重合分辨时间（CRT）和DOI分辨率。
方法：CLSPET探测器在二维晶体阵列中使用三层反射材料，在一对晶体内形成环形结构，实现约300ps的CRT和从多像素光子计数器(MPPC)输出比获取DOI。晶体为1.45×1.45×15mm3fastLGSO，并且将晶体阵列光学耦合到MPPC阵列。为了精确的检测器校准,预先减少尽可能多的晶体间散射(ICS)事件是重要的。DOI信息也有望改善CRT，因为它可以估计由于晶体的检测深度而引起的时间延迟。
结果：使用最高MPPC输出的晶体识别和光收集率减少了ICS事件的数量，CRT提高了26%。此外,CRT进一步改进了13%,具有作为能量的函数的时间延迟的线性校正。理想情况下，DOI仅根据光学耦合到相互作用的晶体的MPPC对的输出比进行估算。这是高度准确的，但在实际使用中由于漏光造成的误差较大。以前的方法，它还利用光泄漏来计算输出比，不太准确，但是误差可以减少。使用两种方法的平均值，可以将DOI分辨率提高12%，同时保持较小的误差。
结论：通过应用开发的校准方法，CLSPET探测器实现了251ps的CRT和3.3mm的DOI分辨率。
方法：CLSPET探测器在二维晶体阵列中使用三层反射材料，在一对晶体内形成环形结构，实现约300ps的CRT和从多像素光子计数器(MPPC)输出比获取DOI。晶体为1.45×1.45×15mm3fastLGSO，并且将晶体阵列光学耦合到MPPC阵列。为了精确的检测器校准,预先减少尽可能多的晶体间散射(ICS)事件是重要的。DOI信息也有望改善CRT，因为它可以估计由于晶体的检测深度而引起的时间延迟。
结果：使用最高MPPC输出的晶体识别和光收集率减少了ICS事件的数量，CRT提高了26%。此外,CRT进一步改进了13%,具有作为能量的函数的时间延迟的线性校正。理想情况下，DOI仅根据光学耦合到相互作用的晶体的MPPC对的输出比进行估算。这是高度准确的，但在实际使用中由于漏光造成的误差较大。以前的方法，它还利用光泄漏来计算输出比，不太准确，但是误差可以减少。使用两种方法的平均值，可以将DOI分辨率提高12%，同时保持较小的误差。
结论：通过应用开发的校准方法，CLSPET探测器实现了251ps的CRT和3.3mm的DOI分辨率。
