Subject motion in positron emission tomography (PET) is a key factor that degrades image resolution and quality, limiting its potential capabilities. Correcting for it is complicated due to the lack of sufficient measured PET data from each position. This poses a significant barrier in calculating the amount of motion occurring during a scan. Motion correction can be implemented at different stages of data processing either during or after image reconstruction, and once applied accurately can substantially improve image quality and information accuracy. With the development of integrated PET-MRI (magnetic resonance imaging) scanners, internal organ motion can be measured concurrently with both PET and MRI. In this review paper, we explore the synergistic use of PET and MRI data to correct for any motion that affects the PET images. Different types of motion that can occur during PET-MRI acquisitions are presented and the associated motion detection, estimation and correction methods are reviewed. Finally, some highlights from recent literature in selected human and animal imaging applications are presented and the importance of motion correction for accurate kinetic modelling in dynamic PET-MRI is emphasized.

This article is part of the theme issue ‘Synergistic tomographic image reconstruction: part 2’.

正电子发射断层扫描 (PET) 中的对象运动是降低图像分辨率和质量、限制其潜在功能的关键因素。由于缺乏来自每个位置的足够的测量 PET 数据，对其进行校正很复杂。这对计算扫描期间发生的运动量造成了重大障碍。运动校正可以在图像重建期间或之后的数据处理的不同阶段实施，一旦准确应用，可以显着提高图像质量和信息准确性。随着集成 PET-MRI（磁共振成像）扫描仪的发展，可以同时使用 PET 和 MRI 测量内部器官运动。在这篇综述论文中，我们探讨了 PET 和 MRI 数据的协同使用，以纠正影响 PET 图像的任何运动。介绍了 PET-MRI 采集期间可能发生的不同类型的运动，并回顾了相关的运动检测、估计和校正方法。最后，介绍了最近选定的人类和动物成像应用文献中的一些亮点，并强调了运动校正对于动态 PET-MRI 中精确动力学建模的重要性。

本文是主题“协同断层扫描图像重建：第 2 部分”的一部分。