High Resolution Detectors for Single Photon Cardiac Imaging

单光子发射计算机断层扫描（SPECT）是一种强大的、无创的医学成像方式，可以在数学上重建放射性核素在人类患者或研究动物体内的三维分布。通常，收集到的数据被显示和评估为一组二维图像，通过被调查的器官或病变区域。SPECT允许对所研究区域的功能进行定量研究，因此是理解包括心脏在内的器官和组织生理学的非常有用的工具。SPECT非常常用来识别和定位冠状动脉疾病，现在多达90%的心肌灌注研究都是使用SPECT进行的。因此，SPECT在心脏成像中发挥着至关重要的作用，既能提供诊断，也能提供预后。然而，迫切需要改进目前用于这种成像方式的仪器，并扩大其能力，以充分利用其潜力。目前，SPECT系统的性能经常受到系统中使用的检测器的限制。现代SPECT系统由闪烁晶体耦合到光电倍增管作为探测器组成。SPECT应用中使用的闪烁体的重要要求包括高光输出和高能量分辨率，合理的快速响应和高伽马射线停止效率。理想情况下，闪烁体也应该便宜，坚固耐用，易于制造。目前，NaI（Tl）是SPECT系统中首选的检测器，其相对便宜且光输出相当大。然而，NaI（Tl）较差的能量分辨率往往限制了SPECT的性能。NaI:Tl的能量分辨率受到其相对较差的比例性的限制。如果能获得典型SPECT能量（~140 keV）下具有更高能量分辨率的闪烁体，则可以改善散射抑制的基本过程。此外，如果具有高能量分辨率的闪烁体可用，双同位素成像（SPECT的独特特性）也将成为可能。提出的努力的目标是研究一种新的高分辨率检测器SPECT研究。随着双同位素成像的可能性，散射抑制增强有望实现。第一阶段的项目将旨在证明提出的概念的可行性，而第二阶段的项目将旨在优化新的探测器，实现原型模块和详细的性能评估。公共卫生相关性：拟议的项目将对卫生保健产生重大影响。它将在研究心肌缺血、神经系统疾病和中风、癌症以及肾脏和肝脏功能方面非常有用。

DESCRIPTION (provided by applicant): High Resolution Detectors for Single Photon Cardiac Imaging Single photon emission computed tomography (SPECT) is a powerful, noninvasive medical imaging modality that mathematically reconstructs the three dimensional distribution of a radionuclide throughout the body of a human patient or a research animal. Typically, the collected data are displayed and evaluated as a set of two-dimensional images through the organ or diseased area under investigation. SPECT allows quantitative study of the function in the investigated region and therefore is an extremely useful tool for understanding organ and tissue physiology including that in the heart. SPECT is very commonly used in identifying as well as localizing coronary artery disease and as many as 90% of all myocardial perfusion studies are now performed using SPECT. Thus, SPECT is playing a critical role in cardiac imaging, providing both diagnosis as well as prognosis. However, there is urgent need for improvement in the instrumentation that is currently used for this imaging modality and expand its capabilities in order to exploit its full potential. At present, the performance of SPECT systems often is limited by the detectors used in these systems. Modern SPECT systems consist of scintillation crystals coupled to photomultiplier tubes as detectors. Important requirements for scintillators used in SPECT applications include high light output and high energy resolution, reasonably fast response and high gamma ray stopping efficiency. Ideally, the scintillator should also be inexpensive, rugged and easy to manufacture. Currently, NaI(Tl) is the detector of choice in SPECT systems and it is relatively inexpensive and its light output is fairly large. However, the poor energy resolution of NaI(Tl) often limits SPECT performance. The energy resolution of NaI:Tl is limited by its relatively poor proportionality. If scintillators with higher energy resolution at typical SPECT energies (~140 keV) were available, the essential process of scatter rejection would improve. Furthermore, dual-isotope imaging, which is a unique property of SPECT, would also become possible if scintillators with high energy resolution became available. The goal of the proposed effort is to investigate a new high resolution detector for SPECT studies. Enhanced scatter rejection can be expected along with possibility of dual isotope imaging. The Phase I project will be aimed at demonstrating the feasibility of the proposed concept, while the Phase II project will be aimed at optimization of the new detector, implementation of the prototype module and detailed performance evaluation. PUBLIC HEALTH RELEVANCE: The proposed project will have a major impact on health care. It will be very useful in studying myocardial ischemia, neurological disorder and stroke, cancer as well as kidney and liver functioning.