IMPROVED SPATIAL AND ENERGY RESOLUTION FOR SPECT

该项目的目标是显着改善身体 信噪比（SNR）检测小（约7- 10 mm）结构成像，单光子发射计算 断层扫描（SPECT）。 这项工作的重要性主要体现在 脑血流量和受体结合的研究，以及 心肌灌注 对于诸如此类的SPECT程序， 使用同位素标记的放射性药物， 被认为是SPECT的理想选择（如1-123和T1-201）， 全面的物理设计在这个时候尤为重要。 然而，即使示踪剂标记有放射性核素， 合适的能量（例如，Tc-99 m）最终可用于 常规临床脑和心脏研究，预期 该项目所带来的物理信噪比的改善将 30%-90%用于检测小病变。 成像时降低对比度的物理机制 与今天的最先进的SPECT扫描仪，包括穷人的空间 分辨率、患者体内散射的辐射和准直器 穿透和散射（特别是对于高能同位素）。 几个考虑因素表明，所有这些影响可能是 同时最小化，同时增加物理SNR， 明智地改变物理测量过程。 实验方法将涉及：（a）详细的计算机 模拟SPECT中的整个光子传输， 从理论上理解几何设计考虑， 能量函数，并预测最优设计;（B） 新型高压气体闪烁器的结构和试验 比例摄像机（GSPC），这将改善固有的 探测器空间分辨率（至2 mm）和能量分辨率（至 在140 keV时小于2.5%）;（c）制造准直器 优化SPECT与新的GSPC;和（d）测试的所有 具有物理和拟人幻象的系统。

The goal of this project is to improve markedly the physical signal-to-noise ratio (SNR) for the detection of small (about 7- 10mm) structures imaged with single-photon emission computed tomography (SPECT). The work will find importance primarily in studies of brain blood flow and receptor binding, as well as myocardial perfusion. For SPECT procedures such as these, the use of radiopharmaceuticals labeled with isotopes that are not considered ideal for SPECT (such as 1-123 and T1-201) renders a thorough physical design particularly important at this time. However, even when tracers labeled with a radionuclide of more suitable energy (e.g., Tc-99m) ultimately become available for routine clinical brain and heart studies, the expected improvement in the physical SNR resulting from this project will be 30%-90% for the detection of small lesions. The physical mechanisms which degrade contrast when imaging with today's state-of-the-art SPECT scanners include poor spatial resolution, radiation scattered in the patient, and collimator penetration an scatter (particularly for high energy isotopes). Several considerations indicate that all of these effects may be simultaneously minimized while increasing the physical SNR by altering judiciously the physical measurement process. The experimental approach will involve: (a) detailed computer simulation of the entire photon transport in SPECT so as to understand theoretically the geometric design considerations as a function of energy, and to predict optimal designs; (b) construction and testing of a novel, high pressure gas scintillation proportional camera (GSPC) which will improve both the intrinsic detector spatial resolution (to 2mm) and the energy resolution (to less than 2.5% at 140 keV); (c) fabrication of a collimator optimized for SPECT with the new GSPC; and (d) testing of all systems with physical and anthropomorphic phantoms.