Evaluation of imaging systems using the posterior variance of emission counts.
Evaluation of imaging systems using the posterior variance of emission counts.
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DOI：
10.1109/tmi.2013.2265886
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发表时间：
2013-10
影响因子：
10.6
通讯作者：
Moore SC
中科院分区：
文献类型：
--
作者：
Sitek A;Moore SC
我们研究了一种用于感兴趣区域(ROI)估计任务的发射断层成像(ET)成像系统的评估方法。在评估中，我们使用了“发射计数”(EC)的概念，它是在扫描期间每个体素发射的事件数。我们使用ROI EC的后验方差相对于先前ROI EC方差的减少作为主要感兴趣的度量，我们称之为后验方差减少指数(PVRI)。实现较高PVRI的系统被认为优于PVRI较低的系统。该方法与重建方法无关，适用于包括列表模式数据在内的所有光子受限数据类型。我们使用二维层析成像模型对这种方法进行了分析，并将我们的结果与经典的层析采样理论进行了比较。我们发现，使用PVRI指数进行绩效评估与经典理论是一致的。基于EC后验方差的系统评估是一种直观的、有物理意义的方法，可用于评估ROI量化任务中的系统性能。
We investigate an approach to evaluation of emission-tomography (ET) imaging systems used for region-of-interest (ROI) estimation tasks. In the evaluation we employ the concept of “emission counts” (EC), which are the number of events per voxel emitted during a scan. We use the reduction in posterior variance of ROI EC, compared to the prior ROI EC variance, as the metric of primary interest, which we call the “posterior variance reduction index” (PVRI). Systems that achieve a higher PVRI are considered superior to systems with lower PVRI. The approach is independent of the reconstruction method and is applicable to all photon-limited data types including list-mode data. We analyzed this approach using a model of 2-D tomography, and compared our results to the classical theory of tomographic sampling. We found that performance evaluations using the PVRI index were consistent with the classical theory. System evaluation based on EC posterior variance is an intuitively appealing and physically meaningful method that is useful for evaluation of system performance in ROI quantitation tasks.