High Timing Resolution Detector Module for Time-of-Flight PET

描述（由申请人提供）：全身正电子发射断层扫描（PET）成像已成为准确确定许多器官系统原发性和转移性癌病变状态的重要诊断工具。然而，目前的临床PET扫描仪已经接近灵敏度的极限。越来越需要提高PET的信噪比，这将导致更好的病变检测，更短的成像时间，和/或更低的注射剂量。通过提高PET中正电子湮灭的两个背对背511 keV光子检测的重合时间分辨率，从而将飞行时间信息纳入图像重建中，从而获得改进。飞行时间PET （TOF PET）拥有唯一已知的显著降低噪音水平的潜力。该项目的目标是开发一种实用的探测器模块，具有比目前可用的更高的时间分辨率，而不会影响其检测用于TOF PET的511 keV光子的效率。探测器模块开发的关键改进包括为TOF PET提供合适的闪烁体材料（LSO），采用多阳极微通道板光电倍增管（MCP PMT）技术作为光电探测器，以及将闪烁体晶体阵列与多阳极MCP PMT进行一对一耦合。虽然新型掺铈卤化物闪烁体材料（LaBr3）具有比LSO更高的光输出和略快的衰减时间，可能是更好的闪烁体材料选择，在探测器模块中产生更好的时间分辨率，但它的停止功率和光电分数远低于LSO，这降低了探测器模块的效率。此外，我们提出的探测器技术可以应用于其他具有突出潜力的TOF PET闪烁体材料，这些材料目前正在研究或将在未来被发现。本文将通过设计、构建、优化和性能评估等阶段对所提出的探测器模块的可行性进行全面表征。探测器模块的贡献也将通过计算机仿真建模，并通过实验测量验证。由此产生的探测器模块有望通过启用TOF，为提高下一代PET扫描仪的成像性能提供所需的优异定时特性。

DESCRIPTION (provided by applicant): Whole-body positron emission tomography (PET) imaging has become an important diagnostic tool for accurately determining the status of primary and metastatic cancerous lesions of many organ systems. However, current clinical PET scanners have approached the limit of sensitivity. There is an increasing need to improve the signal-to-noise ratio in PET, which will lead to better lesion detection, shorter imaging time, and/or lower injected dose. The improvement can be obtained by improving the coincidence timing resolution in the detection of the two back-to-back 511 keV photons from the positron annihilation in PET so that time-of-flight information can be incorporated into the image reconstruction. Time-of-flight PET (TOF PET) holds the only known potential for a significant reduction in the noise levels. The goal of this project is to develop a practical detector module with superior timing resolution than currently available, without compromising its efficiency for detecting 511 keV photons for application in TOF PET. Critical improvements in the development of the detector module include an appropriate scintillator material (LSO) for TOF PET, a multi-anode microchannel plate photomultiplier tube (MCP PMT) technology as the photodetector, and one-to-one coupling of an array of scintillator crystals to the multi-anode MCP PMT. Although the new cerium-doped halide scintillator material (LaBr3) with higher light output and slightly faster decay time than LSO might be a better choice of scintillator material to produce better timing resolution in the detector module, it has much lower stopping power and photoelectric fraction than LSO, which degrades the efficiency of the detector module. Furthermore, the detector technology we propose to develop can be applied to other scintillator materials with outstanding potential for TOF PET that are being currently investigated or will be discovered in the future. The feasibility of the proposed detector module will be thoroughly characterized through the phases of design, construction, optimization, and performance evaluation. The contribution of the detector module will also be modeled through computer simulation and validated by the experimental measurement. The resulting detector module is expected to provide the excellent timing properties needed for improving the imaging performance of next generation PET scanners by enabling TOF.