Maximizing sensitivity for ultra-low dose PET imaging

最大限度提高超低剂量 PET 成像的灵敏度

基本信息

批准号：
10606547
负责人：
Junwei Du
金额：
--
依托单位：
UNIVERSITY OF CALIFORNIA AT DAVIS
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-01 至 2025-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10606547
关键词：
Animals Area Background Radiation Biochemical Biological Assay Biological Models Biological Monitoring Biological Process Bismuth Cardiac Cardiovascular system Cells Circulation Clinical Research Code Coupled Dedications Development Diameter Disease model Dose Electronics Event Funding Geometry Goals Heart Hybrids Image Imaging Techniques Individual Length Low Dose Radiation Lutetium Magnetic Resonance Imaging Measurement Methods Modeling Mus Noise Outcome Performance Polishes Positioning Attribute Positron-Emission Tomography Property Radioisotopes Rattus Receptor Gene Resolution Signal Transduction Source System Therapeutic Thick Work analog cardiovascular imaging clinical diagnostics cost data acquisition design detector glucose metabolism heart imaging image translation imaging modality improved in vivo meter molecular imaging nanomolar novel pre-clinical pre-clinical research preclinical imaging preclinical study radiotracer receptor therapeutic gene tool transgene expression

项目摘要

Summary Small-animal positron emission tomography (PET) has been widely used as a powerful tool for preclinical studies to image a wide range of biological processes in vivo. The key parameters in PET are its spatial resolution and sensitivity that determine the ability to image and quantify radiotracers in a small region of the subject at sub- nanomolar concentrations. However, the applications of small-animal PET have been limited in its application by a combination of spatial resolution and more importantly, the sensitivity, which hampers the use of PET for a range of applications including imaging of low-levels of receptor and transgene expression, imaging of therapeutic cell circulation and fast dynamic imaging to capture cardiac dynamics. The main goal of this proposal is to develop a very high sensitivity total-body small-animal PET scanner dedicated for ultra-low dose and fast dynamic applications for imaging mouse/rat disease models. The proposed PET scanner will have 72 depth-of-interaction (DOI) detector modules arranged in 6 rings, with a ring diameter of 160 mm and an axial length of 242 mm. The geometry of the proposed PET scanner is designed to cover the whole body of the mouse/rat and to obtain high sensitivity and high resolution across the entire body. Dual-ended readout detectors based on SiPMs coupled to both ends of bismuth germanate (BGO) will be used to extract DOI information to maintain high and uniform spatial resolution across the whole field of view (FOV). BGO is chosen due to its high stopping power, high photoelectric ratio, low cost and the most importantly its negligible background radiation (which can significantly reduce the background events to benefit ultra-low dose imaging). While lutetium-based scintillators have many attractive properties, a major limitation is the presence of intrinsic background radiation, which is a significant barrier for ultra-low dose imaging. Dedicated data acquisition electronics will be designed for the proposed scanner. Specifically, a novel analog signal multiplexing readout method using Schottky diodes to block the noise of SiPMs with negligible signals will be used to simplify the readout electronics and to improve the spatial resolution and the timing resolution, and a shared-photodetector readout method will be used to identify all the crystals. The outcome of this proposal will be a PET scanner will have a sensitivity >50% at the center of the FOV and a sensitivity > 40% within the central 100 mm of the axial FOV. The resolution is predicted to be ~ 1 mm at the center of the FOV and better than 1.5 mm across the entire FOV. The sensitivity is more than 4x better than currently available small-animal PET scanners. It can potentially promote the use of total-body small-animal PET for monitoring biological processes that result in very low source activities and expand the range of applications for this powerful, non-invasive and translational imaging modality in preclinical applications. The PET scanner developed in this proposal is also MRI-compatible and will support eventual integration inside an MRI scanner for hybrid PET/MRI imaging.

概括小动物正电子发射断层扫描（PET）已被广泛用作临床前研究的强大工具在体内成像广泛的生物过程。宠物的关键参数是其空间分辨率和敏感性决定了在亚sub-下的小区域中成像和量化放射性示意剂的能力纳摩尔浓度。但是，小动物宠物的应用在其应用中受到限制通过空间分辨率的结合，更重要的是，灵敏度阻碍了宠物的使用应用范围包括低水平受体和转基因表达的成像，成像的成像治疗性细胞循环和快速动态成像以捕获心脏动力学。该提议的主要目标是发展出非常高灵敏度的总体型小动物PET扫描仪用于成像小鼠/大鼠疾病模型的超低剂量和快速动态应用。提议 PET扫描仪将在6环中排列的72个相互作用（DOI）检测器模块，一个环直径 160毫米，轴向长度为242毫米。拟议的PET扫描仪的几何形状旨在覆盖小鼠/大鼠的全身，并在整个身体中获得高灵敏度和高分辨率。将使用基于sipms耦合到德国双端（BGO）两端的sipms的双读数读数检测器（BGO）提取DOI信息，以维持整个视野（FOV）的高空间分辨率。 BGO之所以选择其高停止功率，光电比，低成本，最重要的是它可忽略的背景辐射（这可以显着减少背景事件以使超低剂量受益成像）。虽然基于lutetium的闪光灯具有许多吸引人的特性，但主要限制是存在固有的背景辐射，这是超低剂量成像的重要障碍。专用数据采集电子将为拟议的扫描仪设计。具体而言，一种新颖的模拟使用Schottky二极管使用Schottky二极管来阻止用微不足道的sipm的噪声的信号多路复用读数方法将用于简化读出电子设备并改善空间分辨率和计时分辨率，并且共享 - 示波器读数方法将用于识别所有晶体。该提案的结果将是PET扫描仪在FOV中心的灵敏度> 50％，并且灵敏度> 40％在轴向FOV的中央100毫米内。该分辨率预计为约1毫米 FOV的中心，整个FOV的1.5毫米优于1.5毫米。灵敏度比4倍以上目前可用的小动物宠物扫描仪。它可能会促进总体小动物宠物的使用用于监视导致非常低源活动并扩大应用范围的生物过程对于临床前应用中的这种强大，非侵入性和转化成像方式。宠物扫描仪在此提案中开发的也是MRI兼容的，它将支持MRI扫描仪内部最终集成用于混合宠物/MRI成像。