I. Introduction
Medical image registration refers to the process of aligning medical images obtained at different times, from different imaging devices, or from different anatomical positions. This is an important research direction in the field of medical imaging, which is widely used in image-guided medical image analysis, radiotherapy planning, image guidance for surgery, motion tracking, segmentation, image reconstruction, and other fields [1],[2]. Medical image registration methods can be roughly divided into two categories: those using traditional methods and those using deep learning-based methods.