Monte Carlo evaluation of Compton scatter subtraction in single photon emission computed tomography.
Monte Carlo evaluation of Compton scatter subtraction in single photon emission computed tomography.
复制标题
单光子发射计算机断层扫描中康普顿散射减法的蒙特卡罗评估。
DOI：
10.1118/1.595663
复制
发表时间：
1985
期刊：
影响因子：
3.8
通讯作者：
Coleman,RE
中科院分区：
文献类型：
--
作者：
Floyd,CE;Jaszczak,RJ;Harris,CC;Greer,KL;Coleman,RE
在单光子发射计算机断层扫描 (SPECT) 中，康普顿散射产生的背景会降低图像质量并导致定量测量错误。先前已报道了一种临床上可实施的补偿算法，该算法从在光峰值窗口中获取的主图像中减去在设置为低于光峰值能量的能量窗口中获取的康普顿散射图像。我们对之前减法算法的实证开发中所做的假设进行了评估和论证。使用 SPECT 系统的蒙特卡罗模型来评估这种减法技术，其中康普顿散射事件可以独立于非散射事件进行跟踪。仿真表明该算法在实验应用中所做的假设是有效的。具体来说（1）实验中使用的“散射”能量窗口（91-125 keV，用于成像 Tc-99m）仅包含散射事件，（2）散射窗口中事件的线扩散函数（LSF）的形状是光峰值窗口中散射形状的合理近似，（3）光峰值窗口中散射事件数量与散射窗口中事件数量的比率为 0.57， 接近启发式得出的值 0.5。因此，蒙特卡洛模拟验证了散点减法算法的经验实现背后的基本假设。
In single photon emission computed tomography (SPECT), Compton scattering produces a background that degrades the image quality and contributes erroneously to quantitative measurements. A clinically implementable compensation algorithm has previously been reported that subtracts a Compton scatter image, acquired in an energy window set below the energy of the photopeak, from the primary image acquired in the photopeak window. We present an evaluation and justification of the assumptions made in the previous empirical development of the subtraction algorithm. A Monte Carlo model of the SPECT system in which the Compton scattered events may be followed independently of the nonscattered events was used to evaluate this subtraction technique. Simulation shows that the assumptions made in the experimental application of this algorithm were valid. Specifically (1) the “scatter” energy window used in the experiment (91–125 keV for imaging Tc‐99m) contains only scattered events, (2) the shape of the line spread function (LSF) for the events in the scatter window is a reasonable approximation to the shape of the scatter in the photopeak window, and (3) the ratio of the number of scattered events in the photopeak window to the number of events in the scatter window is 0.57, close to the value of 0.5 derived heuristically. Thus, Monte Carlo simulation validates the basic assumptions underlying the empirical implementation of the scatter subtraction algorithm.