RADIONUCLIDES--RADIATION DETECTION AND QUANTIFICATION

到目前为止，核医学中的所有单张照片成像系统都使用 机械准直以形成放射性同位素分布的图像 在伽马相机的表面上。这些准直器施加了一种困难的物理 将检测灵敏度和空间分辨率结合在一起的限制 反向关系：对于固定的视场，可以提高 分辨率降低2倍，仅通过将灵敏度降低1倍 四。此外，准直器的性能通常会降低 基本上是随着伽马射线能量的增加。这项提案的重点是 是为了确定康普顿相机成像在SPECT和 对其性能进行实验表征。与机械的对比 准直，空间分辨率和噪声等效灵敏度 可以增加。要展示实用性，需要有以下方法 发展为具有系统的成像系统的图像重建 该矩阵可以轻松接近10E 10个字节。方法将是 研究以减少此矩阵的大小，以允许近似 图像重建的解析解决方案，还将采用列表- 模式似然作为一种精确的基于统计的算法。噪声 各种系统配置的等效性能将为 使用表征性能的统一边界技术确定 仅基于系统矩阵和给定对象的限制。蒙特卡洛 研究将用于开发和测试分析系统模型和 还可以生成用于测试图像重建的模拟数据集 以及确认从边界计算中得出的推论。康普顿 相机模块将使用多个硅垫探测器构建 使用自触发式多通道集成电路进行读出 智能读出电路。它将被组装成一个环 用于形成环形康普顿相机(RCC)的闪烁探测器 证明基于康普顿成像原理的系统是 对SPECT成像有明显的优势。

To date, all single photo imaging systems in Nuclear Medicine use mechanical collimation to form an image of the radioisotope distribution on the face of a gamma camera. These collimators impose a hard physical constraint that couples detection sensitivity and spatial resolution in an inverse relationship: for a fixed field of view, one can improve the resolution by a factor of two only by reducing sensitivity a factor of four. Furthermore, collimator performance in general degrades substantially as gamma-ray energy increases. The focus of this proposal is to determine the practicality of Compton camera imaging for SPECT and experimentally characterize its performance. In contrast to mechanical collimation, both spatial resolution and noise equivalent sensitivity can be increased. Demonstration of practicality requires approaches be developed to image reconstruction for an imaging system with a system matrix that can easily approach 10E+10 bytes. Methods will be investigated to reduce this matrix size that permit approximate analytical solutions to image reconstruction and will also employ list- mode likelihood as an exact, statistically based algorithm. Noise equivalent performance for various system configurations will be determined using uniform bound techniques which characterize performance limits based only on the system matrix and a given object. Monte Carlo studies will be used to develop and test analytical system models and also to generate simulated data sets for testing image reconstruction and confirming inferences drawn from bound calculations. The Compton camera module will be constructed using multiple silicon pad detectors read out with self-triggered multi-channel integrated circuits and intelligent read-out circuitry. It will be assembled with a ring scintillation detector to form a Ring Compton Camera (RCC) to demonstrate that a system based on the Compton imaging principles is markedly superior for SPECT imaging.