An Anger Approach for 1mm-Resolution Small-Animal PET

描述（申请人提供）：正电子发射断层扫描（PET）是一种强大的成像工具，用于研究生物体的生物功能。大鼠和转基因小鼠等小动物可作为研究人类疾病和功能的灵活替代物。因此，小动物PET已经成为解决人类健康问题的一种快速增长的方法，从成瘾到癌症再到药物开发。然而，目前最好的PET技术（~2mm分辨率）在空间分辨率和灵敏度上仍然有很大的局限性，特别是对于小鼠。目前提出的提高分辨率的方法面临着许多技术障碍，这些障碍迫使人们在性能上进行权衡。这个项目的目标是证明一种新型的、高性能的、用于小动物PET的伽马射线探测策略的可行性。它本质上是一个小型化和现代化的“愤怒”（或“伽马”）相机，其原理类似于众所周知的单光子发射计算机断层扫描（SPECT）探测器，其中使用连续闪烁晶体，并通过光电探测器组之间的光共享来确定位置。与传统设计相比，关键的改进包括更适合PET （LSO）的闪烁体，更高分辨率的更薄晶体，以及作为光电探测器的大面积雪崩光电二极管（APD）技术，该技术允许分层提高灵敏度，以及其他好处。尽管可能有许多不同的实现，但本提案的目标是开发一种实用的PET探测器，如果用于小动物断层成像，则在大多数视场范围内实现1毫米FWHM的均匀空间分辨率，灵敏度大于大多数小动物探测器设计，并且更具成本效益。所提出的探测器设计的可行性将通过原型构建、性能评估、计算机仿真开发和验证以及最后的优化阶段进行彻底的表征。由此产生的优化设计有望为小动物PET成像提供无与伦比的性能特征组合。

DESCRIPTION (provided by applicant): Positron emission tomography (PET) is a powerful imaging tool to investigate biological function in living organisms. Small animals such as rats and transgenic mice serve as flexible surrogates for studying human disease and function. Consequently, small-animal PET has become a rapidly growing approach to problems in human health, from addiction to cancer to drug development. However, the best currently available PET technology (~2mm resolution) still has significant limitations in spatial resolution and sensitivity, particularly for the mouse. And currently proposed approaches to improve resolution face a number of technical obstacles which force trade-offs in performance. The goal of this project is to demonstrate the feasibility of a novel, high-performance, gamma-ray detection strategy for small-animal PET. It is essentially a miniaturized and modernized "Anger" (or "gamma") camera, with a principle similar to well-known detectors for single-photon emission computed tomography (SPECT), in which a continuous scintillator crystal is used and position is determined from light-sharing among groups of photodetectors. Critical improvements over the traditional design include a more appropriate scintillator for PET (LSO), a thinner crystal for higher resolution, and large-area avalanche photodiode (APD) technology as the photodetector which allows layering to improve sensitivity, among other benefits. Although many different implementations are possible, the target in this proposal is to develop a practical PET detector which, if used in a small-animal tomograph, achieves a uniform spatial resolution of 1 mm FWHM across most of the field-of-view, sensitivity larger than most small-animal detector designs, and a more cost-effective construction. The feasibility of the proposed detector design will be thoroughly characterized through the phases of prototype construction, performance evaluation, computer simulation development and validation, and finally optimization. The resulting optimized design is expected to provide an unparalleled combination of performance characteristics for small-animal PET imaging.