Dept. of Electr. Eng., Washington Univ., St. Louis, MO.
IEEE Trans Med Imaging. 1993;12(3):560-5. doi: 10.1109/42.241884.
A fully three-dimensional (3-D) implementation of the maximum a posteriori (MAP) method for single photon emission computed tomography (SPECT) is demonstrated. The 3-D reconstruction exhibits a major increase in resolution when compared to the generation of the series of separate 2-D slice reconstructions. As has been noted, the iterative EM algorithm for 2-D reconstruction is highly computational; the 3-D algorithm is far worse. To accommodate the computational complexity, previous work in the 2-D arena is extended, and an implementation on the class of massively parallel processors of the 3-D algorithm is demonstrated. Using a 16000- (4000-) processor MasPar/DECmpp-Sx machine, the algorithm is demonstrated to execute at 2.5 (7.8) s/EM-iteration for the entire 64x64x64 cube of 96 planar measurements obtained from the Siemens Orbiter rotating camera operating in the high-resolution mode.
本文展示了一种完全三维（3-D）实现的最大后验（MAP）方法，用于单光子发射计算机断层扫描（SPECT）。与生成一系列单独的 2-D 切片重建相比，3-D 重建显示出分辨率的大幅提高。正如已经指出的，用于 2-D 重建的迭代 EM 算法计算量非常大；3-D 算法则更糟糕。为了适应计算复杂性，对 2-D 领域的先前工作进行了扩展，并展示了该算法在大规模并行处理机类上的实现。使用 16000-（4000-）处理器的 MasPar/DECmpp-Sx 机器，算法在整个 64x64x64 立方体上的 96 个平面测量值中执行，这些测量值是从西门子 Orbiter 旋转相机在高分辨率模式下获得的，每个 EM 迭代需要 2.5（7.8）秒。
