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

 描述（由申请人提供）：小动物PET研究对于新药和疗法的开发以及生物体中各种生化和生理过程的量化至关重要。然而，小动物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，并且通常会导致空间分辨率和灵敏度等关键性能指标之间的权衡。在大多数现代PET系统和正在开发的那些系统中使用的光吸收剂是高密度原硅酸盐基材料，例如LYSO、LSO、LGSO和GSO，这是由于它们的高阻止能力、快速衰减时间、非吸湿性和相对高的光输出。这些闪烁体被机械地像素化以形成闪烁体元件的阵列，以实现 高空间分辨率。然而，使用具有小横截面（例如， 1 × 1 mm 2）和大厚度（例如15 mm）的晶体是具有挑战性的且昂贵的，这导致许多问题，例如光收集问题、精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。在机械像素化阵列中，在像素之间插入反射材料，这导致低填充分数，从而损失对伽马射线的灵敏度。我们的目标是使用最近出现的称为激光诱导光学屏障（LIOB）的技术来开发PET探测器，其中我们在闪烁探测器内创建光学屏障以控制 光扩散函数以及因此的空间分辨率。这项研究工作的意义在于，使用LIOB，开发具有亚毫米固有空间和DOI能力的高灵敏度PET探测器是以非常经济有效的方式实现的。我们的具体目标是：1）模拟激光诱导光垒的性质，并将结果与实验数据相关联。2)对激光加工的探测器进行了建模和光垒图案的优化; 3）制作并表征了LIOB工艺加工的LYSO探测器。

 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.