Gutierrez Benjamin, Badano Aldo, Samuelson Frank
US Food and Drug Administration, Silver Spring, Maryland 20993.
Med Phys. 2014 Jul;41(7):072102. doi: 10.1118/1.4881328.
Variance estimates for detector energy resolution metrics can be used as stopping criteria in Monte Carlo simulations for the purpose of ensuring a small uncertainty of those metrics and for the design of variance reduction techniques.
The authors derive an estimate for the variance of two energy resolution metrics, the Swank factor and the Fano factor, in terms of statistical moments that can be accumulated without significant computational overhead. The authors examine the accuracy of these two estimators and demonstrate how the estimates of the coefficient of variation of the Swank and Fano factors behave with data from a Monte Carlo simulation of an indirect x-ray imaging detector.
The authors' analyses suggest that the accuracy of their variance estimators is appropriate for estimating the actual variances of the Swank and Fano factors for a variety of distributions of detector outputs.
The variance estimators derived in this work provide a computationally convenient way to estimate the error or coefficient of variation of the Swank and Fano factors during Monte Carlo simulations of radiation imaging systems.
探测器能量分辨率指标的方差估计可作为蒙特卡罗模拟中的停止标准，以确保这些指标的不确定性较小，并用于设计方差缩减技术。
作者根据统计矩推导出两个能量分辨率指标（斯旺克因子和法诺因子）的方差估计值，这些统计矩可以在不产生显著计算开销的情况下累积。作者检验了这两个估计器的准确性，并展示了斯旺克因子和法诺因子变异系数的估计值在间接X射线成像探测器蒙特卡罗模拟数据中的表现。
作者的分析表明，对于各种探测器输出分布，其方差估计器的准确性适用于估计斯旺克因子和法诺因子的实际方差。
这项工作中推导的方差估计器为在辐射成像系统的蒙特卡罗模拟过程中估计斯旺克因子和法诺因子的误差或变异系数提供了一种计算方便的方法。
