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，用于研究生物体内的生物功能。小动物，如大鼠和转基因小鼠，可以作为研究人类疾病和功能的灵活替代品。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，从上瘾到癌症到药物开发。然而，目前最好的PET技术(~2 mm分辨率)在空间分辨率和灵敏度方面仍然有很大的限制，特别是对于鼠标。目前提出的提高分辨率的方法面临许多技术障碍，这些障碍迫使在性能上进行权衡。该项目的目标是论证一种新的、高性能的伽马射线检测策略用于小动物PET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，其中使用连续的闪烁体晶体，并根据光探测器组之间的光共享来确定位置。与传统设计相比的关键改进包括更适合于PET(LSO)的闪烁体、更薄的晶体以实现更高的分辨率，以及作为光电探测器的大面积雪崩光电二极管(APD)技术，该技术允许分层以提高灵敏度等优点。虽然可能有许多不同的实施方案，但本建议的目标是开发一种实用的PET探测器，如果用于小动物断层摄影术，在大多数视场范围内实现1 mm半高宽的统一空间分辨率，灵敏度高于大多数小动物探测器设计，并且结构更具成本效益。所提出的探测器设计的可行性将通过原型构建、性能评估、计算机模拟开发和验证以及最后的优化阶段来彻底表征。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.