PET Detector for Cardiac Imaging of Small Animals

描述（由申请人提供）：小动物的正电子发射断层扫描（PET）正在成为一种非常强大的工具，可以促进我们对人类疾病（如心脏病和癌症）的了解。由于小（亚毫米）的特征尺寸，需要专用的高分辨率PET系统来获得感兴趣器官的足够详细的图像。特别是，亚毫米级的空间分辨率需要对小鼠进行详细的功能性心脏成像。目前，大多数PET系统的探测器都是基于密集闪烁体阵列（即间接探测器）。仿真结果表明，闪烁体阵列的间距是限制空间分辨率的主要因素。然而，制造和准确解码元件尺寸远小于1毫米的闪烁体是非常具有挑战性的。此外，随着闪烁体元件尺寸的减小，光收集量减少，从而导致系统的能量和时间分辨率降低。因此，需要一种替代方法来开发用于小动物PET成像的改进检测器。第一阶段研究的主要目标是证明使用室温CdTe和CZT探测器的直接检测方法生产用于小动物成像的高分辨率PET探测器的可行性。我们计划在提议的工作中使用的整体探测器设计预计将满足小动物成像的所有主要要求，包括非常高的空间分辨率，相当高的灵敏度，以及良好的时序和DOI分辨率。从所提出的设计中还可以期望获得出色的能量分辨率。这项提议的努力预计将在其研究潜力和商业范围方面具有持久的价值。这里讨论的最直接的应用是小动物PET成像，它对增加我们对人类疾病模型的理解显示出巨大的希望。其他选定的人类高分辨率PET应用于乳腺、脑和儿科成像，也出现了该技术适用的地方。所提出的技术也可以在正在开发的PET/CT和PET/MRI联合成像仪器中发挥作用。

DESCRIPTION (provided by applicant): Positron emission tomography (PET) of small animals is emerging as a very powerful tool for advancing our understanding of human diseases such as heart disease and cancer. Due to the small (sub-millimeter) feature sizes, dedicated, high resolution PET systems are required to obtain sufficiently detailed images of organs of interest. In particular, sub-millimeter spatial resolution is required for detailed, functional heart imaging of mice. Currently, the detectors for most PET systems are based on arrays of dense scintillators (i.e. indirect detectors). Simulations have shown that the pitch of the scintillator arrays is the dominant factor limiting spatial resolution. However, fabricating and accurately decoding scintillators with element size much smaller than 1-mm is very challenging. In addition, as the scintillator element size decreases, the light collection decreases and consequently the energy and timing resolution of the system decreases. Therefore there is a need for an alternative approach for developing an improved detector for small animal PET imaging. The main objective of the Phase I research is to demonstrate the feasibility of producing very high- resolution PET detectors for small animal imaging using a direct detection approach with room temperature CdTe and CZT detectors. The overall detector design that we plan to use in the proposed effort is expected to satisfy all major requirements for small animal imaging including very high spatial resolution, reasonably high sensitivity, and good timing and DOI resolution. Excellent energy resolution can also be expected from the proposed design. The proposed effort is expected to have a lasting value both in terms of its research potential as well as its commercial scope. The most direct application addressed here is that of small animal PET imaging which is showing enormous promise for increasing our understanding of human disease models. Other selected human high-resolution PET applications for breast, brain and pediatric imaging are also emerging where this technology would be applicable. The proposed technology can also play a role in combined PET/CT and PET/MRI imaging instruments under development.