High speed image registration of head CT and MR images based on Levenberg-Marquardt algorithms

A medical image fusion technique provides insight into lesion diagnosis and spatial relationships among anatomical structures. In radiotherapy planning for CyberKnife treatment, for instance, the accurate area being irradiated is determined and calculated based on a fusion image of CT and MR images. Hence the risk of the normal tissues being irradiated could be brought down. However, commonly used mouse-based registration yields variations in the accuracy of the results due to manual operations. In addition, there are some pending issues such as the increased physical burdens to the operators and the requirement for a substantial investment of time. Therefore, in recent years many researches have attempted to automate the registration for multimodality images. In this paper, a CAD (Computer Aided Diagnosis) system is developed to assist radiotherapy planning for CyberKnife treatment. We propose a new automatic image registration technique for image fusion of head CT (Computed Tomography) and MR (Magnetic resonance) images. In our method, the minimization of ratio image uniformity and the maximization of normalized mutual information on VOIs (Volumes Of Interest) are performed based on Levenberg-Marquardt algorithm. We evaluated our proposed method by 5 clinical cases and discussed the accuracy of the registration results with computational time.