Scintillation Photon Counting Detectors for 100 ps Time-of-Flight PET Imaging

项目摘要 具有良好符合时间的临床飞行时间正电子发射断层扫描（TOF-PET）系统 分辨率（CTR）承诺大大提高有效的511 keV光子灵敏度。能够更精确地 沿沿着系统响应线定位湮灭源约束事件数据，提供改进的信号- 通过将511 keV光子更接近于它们的真实光子， 起源这种SNR增强随着CTR的改善而增加，并且是正在进行的PET仪器的主要目标 研究和发展的目标是推动系统CTR ≤100 ps的半高宽（FWHM）。在这个级别的 性能，事件被限制为≤1.5 cm，相对于 没有TOF能力的系统。能够实现≤100 ps FWHM CTR的先进系统， 与最新技术水平的临床TOF-PET相比，有效的511 keV系统灵敏度提高了一倍或四倍 系统（250-400 ps FWHM CTR）。因此，提高CTR也是大大改善系统的途径 而不增加检测体积和系统成本。标准PET探测器，包括分段 高纵横比闪烁晶体元件的阵列不能达到这种性能水平， 最终受限于较差的光收集效率和深度相关的闪烁光子渡越时间抖动 由光电探测器看到。为了解决这个问题，我们建议开发一种新的探测器读出概念， 闪烁光子被计数，并且在每个时间点为第一到达的光子分配唯一的时间戳 光电传感器像素我们将利用这一可扩展PET探测器读数的新进展， 具有高分辨率、三维定位能力和100 ps FWHM CTR的探测器模块 该设计也不会牺牲511 keV光子探测效率。新的探测器设计将 集成到跨越临床PET系统的整个轴向范围（>20 cm）的大面积探测器模块中， 包括前端信号和后端数据处理。我们将建立一个原型断层成像 设置并量化相关系统性能指标和未来临床系统的成像性能 由这个新的探测器制成。所提出的PET探测器技术可以对以下方面产生重大影响： 定量PET成像。通过有效灵敏度的显著提升实现的图像SNR可以 用于显著减少示踪剂剂量并缩短扫描时间/增加患者吞吐量，或更好地 在存在显著背景的情况下，可视化和量化较小的病变/特征，这很重要 这些功能可以使PET更加实用和准确，并有助于扩大其在患者中的作用。 管理

Project Summary Clinical time-of-flight positron emission tomography (TOF-PET) systems capable of excellent coincidence time resolution (CTR) promise to drastically enhance effective 511 keV photon sensitivity. The ability to more precisely localize annihilation origins along system response lines constrains event data, providing improved signal-to- noise ratio (SNR) and reconstructed image quality by associating 511 keV photons more closely to their true origin. This SNR enhancement increases as CTR is improved, and a major goal of ongoing PET instrumentation research and development is to push system CTR ≤100 ps full-width-at-half-maximum (FWHM). At this level of performance, events are constrained ≤1.5 cm, providing more than a five-fold increase in SNR relative to a system with no TOF capability. Advanced systems capable of ≤100 ps FWHM CTR would effectively more than double or quadruple the effective 511 keV system sensitivity, in comparison to state-of-the-art, clinical TOF-PET systems (250-400 ps FWHM CTR). Thus, advancing CTR is also a pathway for greatly improved system sensitivity without increasing detection volume and system cost. Standard PET detectors comprising segmented arrays of high-aspect-ratio scintillation crystal elements cannot achieve this level of performance and are ultimately limited by poor light collection efficiency and depth-dependent scintillation photon transit time jitter seen by the photodetector. To address this, we propose to develop a new detector readout concept which allows scintillation photons to be counted and a unique timestamp to be assigned for the first arriving photon at each photosensor pixel. We will leverage this new advancement in scalable PET detector readout and produce PET detector modules capable of high resolution, three-dimensional positioning capabilities and 100 ps FWHM CTR in a design that also makes no sacrifices on 511 keV photon detection efficiency. The new detector design will be integrated into large area detector modules that span the full axial extent (>20 cm) of a clinical PET system, including front-end signal and back-end data processing. We will construct a prototype tomographic imaging setup and quantify relevant system performance metrics and the imaging performance of future clinical systems made from this new detector. The proposed PET detector technologies can have a significant impact on quantitative PET imaging. The image SNR enabled by the significant boost in effective sensitivity can be employed to substantially reduce tracer dose and shorten scan time/increase patient throughput, or to better visualize and quantify smaller lesions/features in the presence of significant background, which are important features that can make PET more practical and accurate, as well as help to expand its roles in patient management.