Wang Haibo, Xie Jiahao, Qi Jinyi, Cherry Simon R, Du Junwei
Department of Biomedical Engineering, University of California at Davis, Davis, CA, 95616, USA.
EJNMMI Phys. 2025 May 27;12(1):51. doi: 10.1186/s40658-025-00759-y.
The image quality of positron emission tomography (PET) can be significantly enhanced by using time-of-flight (TOF) and depth-of-interaction (DOI) information. PET detectors are pivotal in determining the TOF and DOI capabilities of PET scanners.
This study developed and evaluated TOF-DOI PET detectors based on the dual-ended readout method and lutetium-yttrium oxyorthosilicate (LYSO) arrays with two different pitches and reflector configurations. Specifically, the performance of detectors based on three types of LYSO arrays with 20 mm thickness, 8 × 8 arrays with a 3.2 mm pitch, 16 × 16 arrays with a 1.6 mm pitch and normal reflectors, and 16 × 16 arrays with a 1.6 mm pitch and partial short reflectors, were assessed. Hamamatsu S14161-3050-08 silicon photomultiplier arrays were used as the photodetectors, and PETsys TOFPET2 was used as the readout electronics.
The flood histograms showed that all crystals in the three types of LYSO arrays were clearly resolved. The detectors based on the 8 × 8 LYSO arrays provided a coincidence timing resolution (CTR) of 207 ± 5 ps and a DOI resolution of 3.9 ± 0.6 mm. The detectors based on the 16 × 16 LYSO arrays with normal reflectors provided a CTR of 218 ± 7 ps and a DOI resolution of 2.6 ± 0.2 mm. In comparison, the detector based on the 16 × 16 LYSO arrays with partial short reflectors provided a CTR of 228 ± 11 ps and a DOI resolution of 2.9 ± 0.3 mm, and superior crystal resolvability compared to the detectors based on the 16 × 16 LYSO arrays with normal reflectors.
These detectors are promising candidates for developing whole-body and brain PET scanners, offering effective sensitivity and uniform spatial resolution improvements across the field-of-view.
通过使用飞行时间（TOF）和相互作用深度（DOI）信息，可以显著提高正电子发射断层扫描（PET）的图像质量。PET探测器对于确定PET扫描仪的TOF和DOI能力至关重要。
本研究基于双端读出方法以及具有两种不同间距和反射器配置的硅酸钇镥（LYSO）阵列，开发并评估了TOF-DOI PET探测器。具体而言，评估了基于三种类型LYSO阵列的探测器性能，这些阵列厚度为20mm，分别是间距为3.2mm的8×8阵列、间距为1.6mm且带有普通反射器的16×16阵列，以及间距为1.6mm且带有部分短反射器的16×16阵列。使用滨松S14161-3050-08硅光电倍增管阵列作为光电探测器，并使用PETsys TOFPET2作为读出电子设备。
泛洪直方图显示三种类型LYSO阵列中的所有晶体都能清晰分辨。基于8×8 LYSO阵列的探测器提供了207±5ps的符合定时分辨率（CTR）和3.9±0.6mm的DOI分辨率。基于带有普通反射器的16×16 LYSO阵列的探测器提供了218±7ps的CTR和2.6±0.2mm的DOI分辨率。相比之下，基于带有部分短反射器的16×16 LYSO阵列的探测器提供了228±11ps的CTR和2.9±0.3mm的DOI分辨率，并且与基于带有普通反射器的16×16 LYSO阵列的探测器相比，具有更好的晶体可分辨性。
这些探测器有望用于开发全身和脑部PET扫描仪，在整个视野范围内提供有效的灵敏度和均匀的空间分辨率提升。
