Non-rigid Image Registration for Medical Diagnosis Using Free-form Deformation with Multiple Grids

〈Summary〉 In recent years, we can get high accuracy cross-sectional images with advanced medical devices such as CT, MRI, and PET, and the images are often vital to medical procedure. Images taken at different times are deformed by visceral movement. The deformations are non-rigid deformation. For medical diagnosis using the images, it is desired to develop a non-rigid image registration. In this research, we register two images that are acquired at different time. We have developed a method for non-rigid image registration, where we use a free-form deformation for image alignment, sum of squared difference as our similarity measurement, and a steepest descent method for optimization. The method achieves improved processing speeds with user interaction for specifying deformation areas.