Hebert T, Leahy R, Singh M
Department of Electrical Engineering, University of Houston, Texas 77204-4793.
J Opt Soc Am A. 1990 Jul;7(7):1305-13. doi: 10.1364/josaa.7.001305.
A three-dimensional maximum-likelihood reconstruction method is presented for a prototype electronically collimated single-photon-emission system. The electronically collimated system uses a gamma camera fronted by an array of germanium detectors to detect gamma-ray emissions from a distributed radioisotope source. In this paper we demonstrate that optimal iterative three-dimensional reconstruction approaches can be feasibly applied to emission imaging systems that have highly complex spatial sampling patterns and that generate extremely large numbers of data values. A probabilistic factorization of the system matrix that reduces the computation by several orders of magnitude is derived. We demonstrate a dramatic increase in the convergence speed of the expectation maximization algorithm by sequentially iterating over particular subsets of the data. This result is also applicable to other emission imaging systems.
针对一种原型电子准直单光子发射系统，提出了一种三维最大似然重建方法。该电子准直系统使用一个由锗探测器阵列前置的伽马相机，来检测来自分布式放射性同位素源的伽马射线发射。在本文中，我们证明了最优迭代三维重建方法可以切实应用于具有高度复杂空间采样模式且会生成极大量数据值的发射成像系统。推导了一种系统矩阵的概率分解，可将计算量减少几个数量级。通过对数据的特定子集依次迭代，我们证明了期望最大化算法的收敛速度有显著提高。该结果也适用于其他发射成像系统。
