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

• 批准号: 8624119
• 负责人: JOEL S KARP
• 金额: $ 23.67万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-30 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8624119
• 关键词: Algorithms; Anatomy; Animals; Anodes; Area; Behavior; Clinical; Collection; Computer Simulation; Computers; Cost Savings; Coupled; Data; Detection; Electronics; Equilibrium; Goals; Image; Lasers; Length; Lesion; Light; Manufacturer Name; Measurement; Measures; Methodology; Modeling; Motion; Noise; Optics; PET/CT scan; Pattern; Performance; Photons; Positioning Attribute; Positron-Emission Tomography; Process; Production; Property; Reading; Research Proposals; Resolution; Sampling; Shapes; Side; Signal Transduction; Site; Surface; System; Technology; Thick; Time; Vendor; Work; attenuation; base; body system; cost; cost effective; design; detector; image reconstruction; improved; instrument; instrumentation; performance tests; public health relevance; research study; response; sensor; thallium-doped sodium iodide; uptake

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、能量和定时分辨率以及高灵敏度的探测器已被各大制造商纳入商业PET/CT扫描仪。这些仪器使用探测器块或模块，其在像素化设计中结合LSO/LYSO闪烁晶体，使得像素的横截面（通常为4 x 4 mm 2）决定空间分辨率。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阻止能力和较长的衰减时间，与21世纪初在PET扫描仪中引入的LSO/LYSO相比，它无法提供具有竞争力的性能。这项研究计划旨在开发一种连续的LYSO检测器模块，以利用这种材料的有利特性，但具有连续检测器的优点。与像素化检测器块相比，我们期望连续检测器对于晶体块内的所有相互作用具有非常均匀的光采样，这导致空间、能量和定时分辨率的优异性能。与像素化检测器相比，在制造连续块检测器中还存在潜在的成本节约，特别是对于需要高空间分辨率的设计。在系统层面上，具有连续定位的探测器能够实现改进的空间和角度采样（没有探测器运动或摆动），这导致改进的图像重建。此外，连续检测器设计适合于测量相互作用深度（DOI），其可用于减小系统视差误差。连续块探测器（其厚度足以实现高灵敏度）中获得优异空间分辨率的关键是控制伽马相互作用位点的光传播。由耦合到闪烁体的一个表面的光电探测器进行的闪烁光子测量的信噪比取决于光响应函数（LRF）并且确定探测器的分辨率。本研究计划的重点是开发和评估的方法，以提高LRF的应用技术的激光诱导光学屏障（LIOB），我们的连续闪烁晶体块。已经证明，LIOB可以在LYSO晶体中产生，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LRF。横向连续位置采样和DOI信息的组合将提高临床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学屏障的行为，2）开发一个计算机模型来优化闪烁晶体中的光响应函数，以提高空间分辨率并实现相互作用深度测量，以及3）测试具有优化布置的激光诱导光学屏障的连续闪烁探测器的性能。