AI 中文总结
该研究提出正交堆叠的xDetector构型，通过优化闪烁体、光电探测器、读出电子学及三维相互作用CTR校正，使系统CTR达108.6 ps FWHM，较传统探测器提升10.3%，有望助力TOF-PET性能提升
AI 中文摘要
研究背景：现有商用飞行时间正电子发射断层成像（TOF-PET）系统的符合时间分辨率（CTR）约为200 ps或更小的半高全宽（FWHM），近期系统级实现100 ps FWHM的CTR成为挑战。传统单端读出方案中，当前硅光电倍增管（SiPM）与20 mm厚闪烁体难以达到100 ps CTR，闪烁体晶体内的光子传输时间展宽（PTS）是主要障碍，相互作用位置差异导致PTS变化达数十ps，降低CTR；缩短闪烁体可提升CTR，但会降低探测效率。方法：为克服CTR与探测效率的权衡，此前提出沿闪烁体晶体纵向轴正交堆叠的xDetector构型，通过优化闪烁体、光电探测器、读出电子学，并基于闪烁体内三维相互作用进行CTR校正，研究xDetector的CTR潜力。主要结果：基于误差传播，成对xDetector的CTR计算值为113.5±2.7 ps FWHM；通过手动滑动xDetector，沿纵向轴四个位置测量其CTR，校正后达到108.6±1.9 ps FWHM；与使用20.0 mm闪烁体的传统单探测器相比，CTR平均提升10.3%。意义：xDetector有望作为PET探测器构型实现100 ps FWHM的CTR，该时间性能有望提升TOF-PET图像质量与定量精度，助力比现有PET探测器更可靠的疾病检测与诊断。
英文摘要
Objective. Existing commercial time-of-flight positron emission tomography (TOF-PET) systems yield a coincidence time resolution (CTR) of ~200 ps or less full width at half maximum (FWHM). Recently, there has been a challenge to achieve a CTR of 100 ps FWHM at the system level. However, current silicon photomultipliers (SiPMs) and 20-mm-thick scintillators in conventional single-ended readout scheme is difficult to achieve 100 ps CTR; the photon transport time spread (PTS) within the scintillator crystal is a major barrier. Differences in the interaction position result in variations in PTS on the order of several tens of ps, thereby degrading the CTR. A shorter scintillator can improve CTR; however, this can degrade detection efficiency. Approach. To overcome this trade-off between the CTR and detection efficiency, we previously proposed xDetector, an orthogonally stacked configuration along the longitudinal axis of scintillator crystals. We investigated the CTR potential of the xDetector by improving the scintillator, photodetector, and readout electronics, and by applying CTR correction based on a three-dimensional interaction within the scintillator. Main results. Based on error propagation, the CTR of the paired xDetector was calculated as 113.5 $\pm$ 2.7 ps FWHM. Furthermore, the CTR of the xDetector was measured at four positions along the longitudinal axis by manually sliding the xDetector, and the corrected achieved CTR was 108.6 $\pm$ 1.9 ps FWHM. Moreover, compared with the conventional single detector using a 20.0 mm scintillator, CTR improved by an average of 10.3%. Significance. The xDetector offers potential as a PET detector concept to achieve a CTR of 100 ps FWHM. Such timing performance is expected to improve TOF-PET image quality and quantitative accuracy, contributing to more reliable disease detection and diagnosis than current PET detectors.
