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Optical Barriers to Improve Performance of a Continuous Detector for Clinical PET

光屏障可提高临床 PET 连续检测器的性能

基本信息

批准号：
8744691
负责人：
JOEL S KARP
金额：
$ 25.37万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-09-30 至 2017-08-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): In recent years detectors with very good spatial, energy, and timing resolution, as well as high sensitivity, have been incorporated into commercial PET/CT scanners by each of the major manufacturers. These instruments use detector blocks, or modules that incorporate LSO/LYSO scintillation crystals in a pixelated design, such that the cross-section of the pixel, typically 4 x 4-mm2, determines the spatial resolution. Continuous scintillation detectors using NaI (Tl) were used in PET for many years, but due to its relatively low stopping power and long decay time it could not provide competitive performance compared to LSO/LYSO introduced in PET scanners in the early 2000's. This research proposal seeks to develop a continuous LYSO detector block to take advantage of the favorable properties of this material, but with the advantages of a continuous detector. Compared to a pixelated detector block, we expect a continuous detector to have very uniform light sampling for all interactions within the crystal block, which leads to excellent performance of spatial, energy, and timing resolution. There are also potential cost savings in manufacturing a continuous block detector compared to a pixelated detector, particularly for designs required high spatial resolution. On a system level, a detector with continuous positioning enables improved spatial and angular sampling (without detector motion or wobbling), which leads to improved image reconstruction. Further, a continuous detector design lends itself to measurement of depth-of-interaction (DOI), which can be used to reduce the system parallax error. The key to excellent spatial resolution in a continuous block detector, which is thick enough to achieve high sensitivity, is to control the spread of light from the site of gamma interaction. The signal-to-noise of the measurement of scintillation photons by the photo-detectors, coupled to one surface of the scintillator, is dependent on the light response function (LRF) and determines the resolution of the detector. The focus of this research proposal is to develop and evaluate the methodology to improve the LRF by applying the technology of laser induced optical barriers (LIOB) to our continuous scintillation crystal blocks. It has been demonstrated that LIOBs can be created in LYSO crystals, therefore, the goal of our work is to determine how to utilize this technology to achieve an optimal LRF in a thick, continuous crystal. The combination of continuous position sampling in the transverse direction and DOI information will improve performance for clinical PET. Our specific aims are 1) characterize the behavior of laser induced optical barriers in continuous scintillation crystals, 2) develop a computer model to optimize the light response function in the scintillation crystal so as to improve spatial resolution and enable depth-of-interaction measurements, and 3) test the performance of a continuous scintillation detector with optimized arrangement of laser induced optical barriers.

描述（由申请人提供）：近年来，具有非常好的空间，能量和时间分辨率以及高灵敏度的探测器已被各大制造商纳入商用PET/CT扫描仪中。这些仪器使用检测器模块，或在像素化设计中包含LSO/LYSO闪烁晶体的模块，这样像素的横截面通常为4 x 4-mm2，决定了空间分辨率。使用NaI （Tl）的连续闪烁探测器已在PET中使用多年，但由于其相对较低的停止功率和较长的衰减时间，与2000年代初引入PET扫描仪的LSO/LYSO相比，它无法提供具有竞争力的性能。本研究计划旨在开发一种连续LYSO探测器块，以利用这种材料的有利性质，但具有连续探测器的优点。与像素化检测器块相比，我们期望连续检测器对晶体块内的所有相互作用具有非常均匀的光采样，从而获得出色的空间，能量和时间分辨率。与像素化探测器相比，制造连续块探测器也有潜在的成本节约，特别是对于需要高空间分辨率的设计。在系统层面上，具有连续定位的检测器可以改善空间和角度采样（没有检测器运动或摆动），从而改善图像重建。此外，连续检测器的设计有助于测量相互作用深度（DOI），这可以用来减少系统视差误差。连续块探测器的厚度足以达到高灵敏度，而获得优异空间分辨率的关键是控制伽马相互作用部位的光传播。光探测器测量闪烁光子的信噪比取决于光响应函数（LRF），并决定了探测器的分辨率。本研究计划的重点是开发和评估将激光诱导光垒（LIOB）技术应用于我们的连续闪烁晶体块来改善LRF的方法。已经证明liob可以在LYSO晶体中创建，因此，我们工作的目标是确定如何利用该技术在厚的连续晶体中实现最佳的LRF。将横向连续位置采样与DOI信息相结合，可以提高临床PET的性能。我们的具体目标是：1)表征连续闪烁晶体中激光诱导光势垒的行为；2)建立一个计算机模型来优化闪烁晶体中的光响应函数，从而提高空间分辨率和实现相互作用深度的测量；3)测试具有优化激光诱导光势垒排列的连续闪烁探测器的性能。