Multimodal images registration constrained by rigid structures with applications in radiotherapy
Abstract (Summary)The main goal of the thesis was the development of a registration method able to match images containing both rigid and non-rigid structures for neck images acquired during the process of radiotherapy. We were interested in developing a volumetric registration method for multimodal images. Specifically we developped an articulated transformation we embedded in the current registration framework. We used physics-based material equations of elasticity to propagate the resulting deformations. This registration method has been used to register articulated structures and was applied to vertebral columns. We have also developed non-rigid registration methods with Mathieu De Craene. The first method is a volumetric and multimodal non-rigid algorithm taking into account the elasticity of the different bodies in the images to register. We used the elastic theory to regularize a deformation maximizing a mutual information criterion. A second method, equivalent of the optical flow but developed for multi-modal images is also described. This method has fewer parameters to adjust but does not take into account the stiffness of the tissues to match. These non-rigid methods have been applied to prostate images, histological sections and to finalize the registration initialized with the articulated registration in the neck area. To assign physical properties, we had to create meshes with good quality elements. We have implemented mesh generators to create the meshes needed to represent the objects to be registered.
Source Type:Master's Thesis
Keywords:neck registration articulations
Date of Publication:10/03/2005