Dept. of Electr. Eng., Houston Univ., TX.
IEEE Trans Med Imaging. 1992;11(1):81-90. doi: 10.1109/42.126914.
In single photon emission computed tomography (SPECT), every reconstruction algorithm must use some model for the response of the gamma camera to emitted gamma-rays. The true camera response is both spatially variant and object dependent. These two properties result from the effects of scatter, septal penetration, and attenuation, and they forestall determination of the true response with any precision. This motivates the investigation of the performance of reconstruction algorithms when there are errors between the camera response used in the reconstruction algorithm and the true response of the gamma camera. In this regard, the authors compare the filtered backprojection algorithm, the expectation-maximization maximum likelihood algorithm, and the generalized expectation maximization (GEM) maximum a posteriori (MAP) algorithm, a Bayesian algorithm which uses a Markov random field prior.
在单光子发射计算机断层扫描（SPECT）中，每个重建算法都必须使用一些模型来描述伽马相机对发射伽马射线的响应。伽马相机的真实响应具有空间变异性和物体依赖性。这两个特性是由散射、隔栅穿透和衰减的影响造成的，因此无法精确确定真实响应。这促使人们研究当重建算法中使用的相机响应与伽马相机的真实响应之间存在误差时，重建算法的性能。在这方面，作者比较了滤波反投影算法、期望最大化最大似然算法和广义期望最大化（GEM）最大后验（MAP）算法，这是一种使用马尔可夫随机场先验的贝叶斯算法。
