TlBr Detectors for High Resolution PET Imaging

描述（由申请人提供）：溴化铊（TlBr）是一种很有前途的半导体，可作为核医学应用的直接g射线探测器，特别是用于正电子发射断层扫描（PET）。它具有极高的检测效率、优异的空间分辨率、低噪声和高能量分辨率的潜力。TlBr具有高z组分、高密度、宽半导体带隙等特点，根据材料纯化和生长的最新进展，可以制备出具有良好电子电荷输运参数的TlBr。在室温下工作的小型半导体探测器具有高空间分辨率、高探测效率和良好的能量分辨率，将比LSO、BGO和CdTe/CZT这些在小动物PET应用中最常见的g射线探测器材料具有独特的优势。事实上，TlBr在511 keV时比目前PET扫描仪中使用的任何其他材料都具有更好的停止功率。高性能PET检测器模块可用于构建能够成像小鼠脑内亚结构的扫描仪，或定量评估小鼠癌症模型中的肿瘤异质性和微环境。我们相信，这一提案将开发出世界上第一个基于tlbr的PET探测器模块，将能够使这一有前途的技术达到商业开发的可能。本提案的目标是开发两个高灵敏度TlBr探测器模块和相关电子器件，其固有空间定位在二维上为0.5 mm，在三维上为2.5 mm

DESCRIPTION (provided by applicant): Thallium bromide (TlBr) is a promising semiconductor for use as a direct g-ray detector for nuclear medicine applications, especially for positron emission tomography (PET). It has the potential to provide very high detection efficiency, excellent spatial resolution, low noise and high-energy resolution. TlBr has high-Z constituents, high density, a wide semiconducting bandgap, and based on recent progress with material purification and growth, can be produced with good charge transport parameters for electrons. A compact semiconductor detector operating at room temperature with high spatial resolution, high detection efficiency and good energy resolution would offer unique advantages over LSO, BGO, and CdTe/CZT, which are the most common g-ray detector materials in small animal PET applications. Indeed, TlBr has better stopping power at 511 keV than any other material currently used in PET scanners. High performance PET detector modules could be utilized to build a scanner able to image substructures within the mouse brain, or to quantitatively assess tumor heterogeneity and microenvironment in a mouse cancer model. We believe that this proposal, which will develop the world's first TlBr-based PET detector modules, will be able to bring this promising technology to a point where its commercial exploitation will be possible. The goal of this proposal is to develop two high-sensitivity TlBr detector modules and associated electronics with intrinsic spatial localization of 0.5 mm in two dimensions and 2.5 mm in the third (depth) dimension. The specific aims address steps needed to produce detector modules from existing high quality detector grade TlBr ingots grown by the travelling molten zone method. The ingots are large enough (30 mm and 50 mm diameter) to cut substrates from which monolithic 20 mm x 20 mm detectors can be fabricated. We will: (1) optimize material processing for planar detector fabrication; (2) produce and test single cross-strip detectors; (3) implement multiplexed multi-channel readout and characterize detector performance in that configuration; (4) build two modules of stacked detectors and use them in a benchtop system to evaluate PET imaging performance. Monte Carlo simulations, incorporating experimentally-measured detector data, will also be used to predict the performance of complete small-animal PET scanners based on these TlBr detector modules. These aims will provide the necessary developments in process and design to produce usefully large-area and high-performance detector modules made from TlBr, aimed initially at providing the sub-mm spatial resolution and high detection efficiency needed for small-animal PET applications.