Calibration Method for ML Estimation of 3D Interaction Position in a Thick Gamma-Ray Detector.
Calibration Method for ML Estimation of 3D Interaction Position in a Thick Gamma-Ray Detector.
复制标题
DOI：
10.1109/tns.2008.2010704
复制
发表时间：
2009-02-10
影响因子：
1.8
通讯作者：
Furenlid LR
中科院分区：
文献类型：
--
作者：
Hunter WC;Barrett HH;Furenlid LR
高能（> 100 keV）光子探测器通常相对于它们的横向分辨率被制造得较厚，以便提高它们的光子探测效率。为了避免随机相互作用深度导致的视差和信号方差增加的问题，我们必须确定成像探测器中的3D相互作用位置。考虑到这一目标，我们研究了一种校准厚探测器伽马相机响应统计数据的方法，以产生3D交互位置的最大似然估计。我们参数化的平均检测器响应作为一个函数的3D位置，我们估计这些参数，通过最大限度地提高他们的可能性给定的路径长度分布的先验知识和完整的列表的相机信号的伽玛射线相互作用的合奏。此外，我们描述了一种迭代方法，用于从我们的校准数据中去除多个相互作用事件，并用于改进我们对单个相互作用的平均检测器响应的校准。我们证明了这种校准方法与模拟伽马相机数据。然后，我们表明，由此产生的校准是准确的，可以用来产生无偏估计的三维相互作用的位置。
High-energy (> 100 keV) photon detectors are often made thick relative to their lateral resolution in order to improve their photon-detection efficiency. To avoid issues of parallax and increased signal variance that result from random interaction depth, we must determine the 3D interaction position in the imaging detector. With this goal in mind, we examine a method of calibrating response statistics of a thick-detector gamma camera to produce a maximum-likelihood estimate of 3D interaction position. We parameterize the mean detector response as a function of 3D position, and we estimate these parameters by maximizing their likelihood given prior knowledge of the pathlength distribution and a complete list of camera signals for an ensemble of gamma-ray interactions. Furthermore, we describe an iterative method for removing multiple-interaction events from our calibration data and for refining our calibration of the mean detector response to single interactions. We demonstrate this calibration method with simulated gamma-camera data. We then show that the resulting calibration is accurate and can be used to produce unbiased estimates of 3D interaction position.