中文摘要：

PET／MRI是近年兴起的新型多模式成像设备。PET图像需要利用衰减图进行衰减校正，从而得到真实的放射性药物浓度的分布信息。PET／MRI利用MRI数据得到衰减图对PET进行校正，其获取衰减图的方法是PET／MRI系统的关键技术。PET／MRI衰减校正的方法主要有分割法、地图集法和发射数据重建法。本文介绍这3种方法的原理、校正效果及优缺点，并对PET／MRI衰减校正技术的发展方向进行展望。

英文摘要：

PET/MRI as a new hybrid imaging device which has developed rapidly in recent years. In order to obtain quantitative activity distribution, an attenuation map is required for PET attenuation correction （AC）. In PET/MRI sys- tem, the attenuation map was obtained from MRI data, and the relative techniques were the key of AC technology. Meth- ods for AC in PET/MRI can be categorized into segmentation method, atlas method and emission-based reconstruction method. The principle, effect, merit and demerit of these methods were described, and the developments of AC in PET/ MRI were reviewed in this article.