Singh M
Med Phys. 1983 Jul-Aug;10(4):421-7. doi: 10.1118/1.595313.
The detection and imaging characteristics of a new type of gamma camera for single photon emission computed tomography have been investigated. Unlike conventional gamma cameras which use mechanical collimation, the new gamma camera utilizes electronic collimation which is obtained from a sequential interaction of gamma radiation with a dual position-and-energy sensitive detection system. Coincident counting between the two detectors provides localization of activity upon a multitude of conical surfaces throughout the object, wherefrom the three-dimensional activity distribution can be reconstructed. Not only does electronic collimation provide simultaneous multiple views of the object, but a large gain in sensitivity is also indicated over a conventionally collimated gamma camera under conditions of similar spatial resolution. Detector optimization studies have been performed to design a prototype system comprising a 33 X 33 array of high-purity germanium detectors coupled to an uncollimated conventional scintillation camera. The cumulative signal-to-noise ratio in projection images obtained with this system is expected to be about a factor of 4 higher (sensitivity about a factor of 15 higher) than that obtained in a corresponding projection image with a conventional gamma camera for imaging a uniformly distributed Tc-99m source in a 20-cm-diam X 20-cm-tall cylinder. A similar gain is expected in the tomographic images.
对一种用于单光子发射计算机断层扫描的新型伽马相机的检测及成像特性进行了研究。与使用机械准直的传统伽马相机不同，新型伽马相机采用电子准直，该电子准直通过伽马辐射与双位置和能量敏感检测系统的顺序相互作用获得。两个探测器之间的符合计数可在整个物体的多个圆锥面上确定放射性的位置，由此可重建三维放射性分布。电子准直不仅能提供物体的同时多视角视图，而且在空间分辨率相似的条件下，与传统准直伽马相机相比，灵敏度也有大幅提高。已开展探测器优化研究，以设计一个原型系统，该系统由33×33阵列的高纯锗探测器与一个非准直的传统闪烁相机组成。预计用该系统获得的投影图像中的累积信噪比约比用传统伽马相机对直径20厘米、高20厘米的圆柱体中均匀分布的Tc - 99m源进行成像时获得的相应投影图像高约4倍（灵敏度约高15倍）。断层图像预计也会有类似的增益。
