New Design of a Sensor for Ultrahigh Performance SPECT Imaging

描述（由申请人提供）：在各种功能成像技术中，SPECT在小动物疾病模型研究和患者护理中保持着重要且日益增长的作用。许多spect标记的成像探针具有高度特异性的分布和很少的背景，被用于测量小动物中广泛的重要生物学参数，包括底物代谢、血流量、缺氧、蛋白质合成和受体特性。近年来，随着转基因在体内表达成像方法的发展，这一重要方式的应用得到了显著增强。此外，SPECT具有双同位素成像能力，可以通过单一成像研究将两个生物过程关联起来。最近对小动物SPECT的需求也受到制药行业的推动，制药行业需要对生物过程进行体内量化，以测量药物的作用机制及其在作用部位的浓度。这些应用都需要出色的空间分辨率，这不仅是因为要成像的细节规模小，而且还因为要求苛刻的检测和估计任务。同时，高灵敏度也是必不可少的，因为它对于减少图像采集时间、提高时间分辨率、增加患者/动物研究的通量以及减少患者剂量至关重要。虽然基于CCD/闪烁体的SPECT探测器的新发展通过展示亚100微米的固有空间精度来解决分辨率问题，但能够同时提供高分辨率和高灵敏度的探测器尚未实现。这主要是由于当前闪烁体中众所周知的效率-分辨率权衡以及任何闪烁体中斜3射线入射引起的视差误差。因此，开发一种新型闪烁体，克服传统的效率-分辨率权衡和实现最小化视差误差的方法，对于实现真正的高分辨率，高灵敏度SPECT探测器至关重要。为了解决这些问题，我们建议开发一种基于独特设计的闪烁体的新型传感器，并结合非常高的空间分辨率读出。具体来说，闪烁体将为SPECT成像中通常使用的3种能量提供非常高的空间分辨率和高灵敏度，并允许对每个事件进行相互作用深度（DOI）估计。读出传感器固有的高空间分辨率，以及DOI信息，将使探测器以经济高效的方式实现极其精细和均匀的空间分辨率和高灵敏度。

DESCRIPTION (provided by applicant): Among the various functional imaging techniques, SPECT maintains an important and growing role in the study of disease models in small animals as well as in patient care. Many SPECT-labeled imaging probes that have highly specific distributions with very little background are being used to measure a wide range of biological parameters of importance in small animals including substrate metabolism, blood flow, hypoxia, protein synthesis and receptor characteristics. The utility of this important modality has been significantly enhanced in recent years by the development of methods to image transgene expression in vivo. Furthermore, SPECT is capable of dual-isotope imaging for correlating two biological processes with a single imaging study. Recent demand for small animal SPECT has also been driven by the pharmaceutical industry, where in vivo quantification of biological processes to measure an agent's mechanism of action and its concentration at the site of action is necessary. Each of these applications requires excellent spatial resolution not only because of the small scale of the details to be imaged but also for demanding detection and estimation tasks. Simultaneously, high sensitivity is also essential, as it is critically important for reducing image acquisition time, improving temporal resolution, increasing throughput for patient/animal studies, and reducing patient dose. While new developments in CCD/scintillator-based SPECT detectors have addressed the resolution issue by demonstrating sub- 100 micron intrinsic spatial accuracies, a detector that can simultaneously provide high-resolution and high- sensitivity has not yet been realized. This is primarily due to the well-known efficiency-resolution tradeoff in current scintillators and the parallax errors arising from oblique 3-ray incidences in any scintillator. Thus, the development of a novel scintillator that can overcome the traditional efficiency-resolution tradeoff and implementation of methodologies to minimize parallax errors is crucial for realizing a truly high-resolution, high- sensitivity SPECT detector. To address these issues, we propose to develop a novel sensor based on a scintillator of a unique design, coupled to a very high spatial resolution readout. Specifically, the scintillator will provide very high spatial resolution and high-sensitivity for 3 energies typically used in SPECT imaging and will permit depth-of- interaction (DOI) estimation for every event. The high spatial resolution intrinsic to the readout sensor, along with the DOI information, will enable the detector to achieve extremely fine and uniform spatial resolution and high sensitivity, in a cost-effective manner. PUBLIC HEALTH RELEVANCE: The goal of the proposed research is to develop a very high performance, cost-effective sensor for small animal single photon emission computed tomography (SPECT) imaging. Among other benefits, SPECT studies are well suited to imaging radiolabeled antibodies and other substances that can be used to localize and characterize tumors in small animals and are well suited to the development of new radiolabeled agents for diagnosing and tracking the treatment of diseases in humans. The development of such a sensor will significantly improve the resolution and sensitivity with which measurements can be made, and this, in turn, will allow the development of superior methods, drugs and technologies to diagnose and stage, and treatments to curtail the progression of and even cure, certain cancers, diseases of the heart and disorders of the circulatory system.