Fast registration technique of MR and SPECT brain images

In this paper, we focus on the 3D registration between the MR and SPECT brain images. It is undoubted that the human brain does not change its shape during imaging processes, registration of these two image sets can be modeled as a rigid body motion problem. Since the size of each voxel in MR and SPECT images is given, our goal is to find out three translation parameters and three rotation parameters of the motion and then match the object to a fixed position. In this paper, a hybrid method composed of homologous feature registration and surface fitting is developed. The centers of the two eyeballs are used as the feature sets for registration. Therefore, we can solve the three translation parameters and two rotation parameters. We then reslice the volume data. The remaining rotation parameter is determined by minimizing the surface distance, in the resliced 2D images. After obtaining all these parameters, the transformation matrix is determined, and the registration is well done.