Optimization of x-ray imaging geometry (with specific application to flat-panel cone-beam computed tomography)
Optimization of x-ray imaging geometry (with specific application to flat-panel cone-beam computed tomography)
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DOI：
10.1118/1.1286590
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发表时间：
2000-08-01
期刊：
影响因子：
3.8
通讯作者：
Jaffray, DA
中科院分区：
文献类型：
--
作者：
Siewerdsen, JH;Jaffray, DA
提出了一种理论方法，允许识别最佳的X射线成像几何形状，考虑X射线源分布，成像任务，X射线的影响。散射和成像器探测量子效率（DQE）。这些因素中的每一个都被纳入ICRU推荐的图像质量品质因数，即可检测性指数，该指数被最大化以确定最佳系统配置。级联系统分析的平板成像器（FPI）的扩展，将直接在DQE的X射线散射的影响，显示X射线散射降低DQE作为一个附加的噪声源。计算适合（但不限于）锥形束计算机断层扫描（CBCT）的FPI配置的最佳放大率。结果的灵敏度被检查为焦斑尺寸、成像任务（例如，理想观察者检测或辨别任务）、X射线散射分数、检测器分辨率和附加噪声。FPI-CBCT的标称条件导致最佳放大倍数为1.4-1.6，主要取决于X射线散射分数的大小。该方法是足够普遍的，用于其他FPI应用（例如，胸部X线摄影、荧光透视和乳房X线摄影）是可能的。增加的曝光量可以用来补偿X射线散射退化的程度是量化的。(C)2000年美国医学物理学家协会。【S0094-2405（00）00708-2】。
A theoretical method is presented that allows identification of optimal x-ray imaging geometry, considering the effects of x-ray source distribution, imaging task, x-ray. scatter, and imager detective quantum efficiency (DQE). Each of these factors is incorporated into the ICRU-recommended figure of merit for image quality, the detectability index, which is maximized to determine the optimal system configuration. Cascaded systems analysis of flat-panel imagers (FPIs) is extended to incorporate the effects of x-ray scatter directly in the DQE, showing that x-ray scatter degrades DQE as an additive noise source. Optimal magnification is computed for FPI configurations appropriate to (but not limited to) cone-beam computed tomography (CBCT). The sensitivity of the results is examined as a function of focal spot size, imaging task (e.g., ideal observer detection or discrimination tasks), x-ray scatter fraction, detector resolution, and additive noise. Nominal conditions for FPI-CBCT result in optimal magnification of similar to 1.4-1.6, depending primarily on the magnitude of the x-ray scatter fraction. The methodology is sufficiently general that examination of optimal geometry for other FPI applications (e.g., chest radiography, fluoroscopy, and mammography) is possible. The degree to which increased exposure can be used to compensate for x-ray scatter degradation is quantified. (C) 2000 American Association of Physicists in Medicine. [S0094-2405(00)00708-2].