High performance PET Detector Module for Human Brain Imaging

项目摘要/摘要 这项建议是对PA 18-484的回应。在大脑2025年报告中，正电子发射断层扫描(PET)是 被认为是将神经递质、受体和神经调节剂的研究转化为 人类。“然而，受体占有率和新陈代谢的动态评估受到空间因素的阻碍 即使是最现代的临床上可用的PET扫描仪，其分辨率和灵敏度也很高。要解决这个问题 挑战，我们提出了一种具有高度创新设计的下一代PET探测器：具有 分层闪烁体结构和侧面读出配置。模块中的水晶片堆叠在一起 沿深度方向，并由反射膜光学分隔。在每一颗行星上产生的闪烁光 由位于晶体四边的光电探测器测量晶体的厚度。与传统聚酯相比 探测器中包含像素化晶体阵列，新设计具有以下优点：(1)分层 结构提供相互作用深度(DOI)信息，使得可以使用较小直径的探测器环 在不增加视差误差的情况下，在降低成本的同时提高灵敏度。(2)四面读数法 提高了系统的能量分辨率，增加了闪烁光收集效率，通过减少 由于全内反射造成的光损失。(3)亚毫米级空间分辨率是可以实现的，而不需要使用非常 小间距晶体阵列，因为每个晶层中的相互作用位置是通过机器学习来确定的。 基于对在四个晶面上收集的光分布的解码。因此，该产品的生产成本 晶体减少了。(4)由于确定了各层的相互作用位置和能量分辨率 独立地，可以通过在模块中堆叠更多层来提高系统灵敏度，而不会影响 系统的空间和能量分辨率。(5)对于侧面读出设置，横截面面积比更大 TO长度需要更少的光电探测器来覆盖模块的所有四个侧面；这降低了光电探测器的成本。 上述前四点已在使用小型原型模块进行的初步研究中进行了演示。我们 提出了用这种新的设计来构建一个大规模的探测器模块，以验证第五个优势，并进行了研究 探测器尺寸对前四个参数的影响。该提议的结果将是两个启用DOI的探测器模块 具有出色的空间分辨率(~1 mm)和能量分辨率(~10%)，以及良好的时间分辨率(~400 Ps)、DOI分辨率(~3 mm)和高系统灵敏度。这两个模块的完整特性研究 对DeRenzo和Hoffman大脑模型的成像研究将解决目前 人脑PET扫描仪，并将作为新的用于神经成像的动态PET扫描仪的基础。

Project Summary / Abstract This proposal is in response to PA 18-484. In the BRAIN 2025 Report, PET (positron emission tomography) is identified as “the best means to translate studies of neurotransmitters, receptors, and neuromodulators to humans.” However dynamic assessment of receptor occupancy and metabolism is hindered by the spatial resolution and sensitivity of even the most modern of clinically available PET scanners. To address this challenge, we propose a next generation PET detector with a highly innovative design: a detector module with a layered scintillator structure and a side readout configuration. The crystal slabs in the module are stacked along the depth direction and are optically separated by reflective films. The scintillation light created in each layer is measured by photodetectors located on the four sides of the crystal. Compared with traditional PET detectors, which contain pixelated crystal arrays, the new design has the following advantages: (1) The layered structure provides depth of interaction (DOI) information such that a smaller diameter detector ring can be used without increasing parallax error, increasing sensitivity while lowering costs. (2) The four-sided readout method improves the energy resolution of the system with increased scintillation light collection efficiency by reducing light loss due to total internal reflection. (3) Sub millimeter spatial resolution is achievable without using very small pitch crystal arrays, since the interaction location in each crystal layer is determined via machine learning- based decoding of the light distribution collected on the four crystal sides. Therefore the production cost of the crystals is reduced. (4) Since the interaction location and energy resolution for each layer are determined independently, the system sensitivity can be increased by stacking more layers in the module without affecting the spatial and energy resolution of the system. (5) For side readout setup, a larger ratio of cross-sectional area to length requires fewer photodetectors to cover all four sides of the module; this reduces photodetector cost. The first four points above have been demonstrated in preliminary studies using a small, prototype module. We propose to build a large scale detector module with this new design to verify the fifth advantage, and to study the effect of detector size on the first four. The outcome of this proposal will be two DOI enabled detector modules with excellent spatial resolution (~1 mm) and energy resolution (~10%), as well as good timing resolution (~400 ps), and DOI resolution (~ 3 mm) and high system sensitivity. A full characterization study for the two modules and imaging studies for both the Derenzo and Hoffman brain phantoms will address the current limitations of human brain PET scanners, and will serve as the foundation for a new dynamic PET scanner for neuroimaging.