| The long-term goal of this research is to develop medical image registration techniques that can improve cancer detection, diagnosis, and therapy. Both rigid-body and deformable image registration methods were developed for human magnetic resonance (MR) images. As reported in Chapter 2, our automatic, three-dimensional (3D), rigid-body registration method has special features that include multi-resolution, multi-similarity, and restarting mechanisms. These features improved the robustness of MR image registration. The automatic registration method has been evaluated for potential applications in prostate MR imaging. However, tissue deformation and patient positions often raise problems for rigid-body registration. In order to improve registration accuracy, 3D thin-plate spline (TPS)-based deformable registration methods were developed and evaluated for pelvic MR images that were acquired at different patient positions/conditions. As described in Chapter 3, our TPS registration methods have several potential applications for image-guided therapy of the prostate. With the recent advancement of small animal imaging technology, MR imaging can provide high-resolution images of a tumor with subtle anatomic details, molecular imaging such as positron emission tomography (PET) can provide functional and metabolic information regarding the tumor. Registration of PET and MR images can combine the strength from the two imaging modalities and thus provides complementary information at the cellular and molecular levels. Chapter 4 proposes and evaluates a finite-element model (FEM)-based registration method for tumor PET and MR images, which can have unique applications in cancer early detection and therapy assessment. Chapter 5 further demonstrates clinical applications of multimodality image registration for prostate cancer patients. Methods were developed for MRI/SPECT registration and CT/SPECT fusion. Finally, Chapter 6 describes the future work of image registration techniques and the conclusion of the research work. |
