Novel laser-processed scintillation detector for high-resolution PET scanners

 描述(由申请人提供)：小动物PET研究在开发新的药物和治疗方法以及量化活体中不同的生化和生理过程中至关重要。然而，小动物体内结构的可视化和量化成像对成像系统提出了严格的要求。同时满足这些要求需要昂贵的方法，通常还会导致在空间分辨率和灵敏度等关键性能指标之间进行权衡。大多数现代PET系统和正在开发的系统中使用的闪烁体是高密度正硅酸盐材料，如LYSO、LSO、LGSO和GSO，这是因为它们具有高阻挡能力、快速衰减时间、非吸湿性和相对较高的光输出。这些闪烁体被机械像素化以形成闪烁体元件阵列，以实现 高空间分辨率。然而，用具有小截面的像素制造阵列(例如 1x1平方毫米)和大厚度(例如15毫米)是具有挑战性和昂贵的，这导致了许多问题，如光收集问题，准确和一致的晶体尺寸的实际困难，以及与精细晶体切割和表面处理(抛光)相关的高成本。在机械像素化的阵列中，在像素之间插入反射材料，这导致低堆积分数，从而对伽马射线失去敏感性。我们的目标是开发一种使用最近出现的称为激光诱导光障(LIOB)的技术的PET探测器，即我们在闪烁探测器中创建光障来控制 光扩散函数，从而提高了空间分辨率。这项研究工作的意义在于，使用LIOB，可以以非常经济高效的方式开发具有亚毫米固有空间和DOI能力的高灵敏度PET探测器。我们的具体目标是：1)模拟激光诱导光学势垒的特性，并将结果与实验数据进行关联。2)建立了激光加工的探测器模型，优化了光学势垒图案；3)制作了激光加工的LYSO探测器，并对其进行了表征。

 DESCRIPTION (provided by applicant): Small animal PET studies are crucial in development of new pharmaceuticals and therapies as well as quantification of diverse biochemical and physiological processes in living organism. Visualized and quantified imaging of structures in small animals, however, imposes stringent requirements on the imaging system. Satisfying these requirements simultaneously necessitates expensive approaches and typically results in trading off between key performance metrics such as spatial resolution and sensitivity. The scintillators used in the majority of the modern PET systems and those under development are high density orthosilicate-based materials such as LYSO, LSO, LGSO, and GSO thanks to their high stopping power, fast decay time, non- hygroscopic nature, and relatively high light output. These scintillators are mechanically pixelated to form an array of scintillator elements to achieve high spatial resolution. However, array fabrication with pixels that have small cross-section (e.g. 1x1 mm2) and large thickness (e.g. 15 mm) is challenging and expensive which leads to a number of issues such as light collection problem, practical difficulties of accurate and consistent crystal size, and high cost associated with fine crystal cutting and surface treatment (polishing). In the mechanically pixelated arrays, a reflecting material is inserted between the pixels which leads to low packing fraction and thereby loss of sensitivity to gamma rays. Our goal is develop a PET detector using recently emerged technology called Laser-Induced Optical barriers (LIOB) in that we create optical barriers within the scintillation detector to control the light spread function and hence the spatial resolution. The significance of this research work is that using LIOB, development of high sensitivity PET detectors with sub-millimeter intrinsic spatial and DOI capability is achievable in a very cost effective manner. Our specific aims are to 1) Simulate the properties of laser induced optical barriers and correlate the results with experimental data. 2) Model a laser processed detector and optimize the optical barriers pattern, and 3) Fabricate and characterize LYSO detectors processed by LIOB technique.