Chen Huafu, Lei Xu, Yao Dezhong
School of Life Science and Technology, University of Electronic Science and Technology of China, 610054 Chengdu, China.
Comput Biol Med. 2007 Dec;37(12):1780-5. doi: 10.1016/j.compbiomed.2007.05.006. Epub 2007 Jul 10.
Ordered subsets expectation maximization (OS-EM) reconstruction method is usually used in positron emission tomography (PET). But it has some disadvantage such as long computation time and bad reconstruction quality. Filtered back projection (FBP), that has many advantages such as simple structure and short reconstruction time, is firstly introduced into the initialization stage of the OS-EM to fast the reconstruction process. Then, the smoothness method is applied after the OS-EM algorithm to improve the reconstruction speed and quality. The reconstructed images are compared for both the simulated phantom data and the brain magnetic resonance imaging data. The improved OS-EM is shown to be more feasible than the standard OS-EM within the same iteration steps and in higher signal noise ratio (SNR) condition.
有序子集期望最大化（OS-EM）重建方法通常用于正电子发射断层扫描（PET）。但它存在一些缺点，如计算时间长和重建质量差。具有结构简单、重建时间短等诸多优点的滤波反投影（FBP）首先被引入到OS-EM的初始化阶段，以加快重建过程。然后，在OS-EM算法之后应用平滑方法来提高重建速度和质量。对模拟体模数据和脑磁共振成像数据的重建图像进行了比较。结果表明，在相同迭代步数和更高信噪比（SNR）条件下，改进后的OS-EM比标准OS-EM更可行。
