Enhancing Liver Radioembolization Precision: Advances in Multimodal Image Registration Based on 3D Slicer and Ellipsoid Modeling

Liver radioembolization is a minimally invasive treatment for liver malignancies, requiring precise imaging to ensure accurate delivery of therapeutic agents. This paper addresses the key challenges in image registration for liver radioembolization, highlighting recent advancements with a focus on the integration of 3D Slicer software and the ellipsoid method. The oriented bounding boxes (OBBs) technique streamlines the representation of complex liver segments, which represent the object's contours. It simplifies them into simple oriented geometric shapes, making them easier to align. These shapes are then mathematically approximated as ellipsoids (a stretched sphere), enabling precise computations such as alignments, which form a central focus of this paper. This study evaluates the impact of using the OBBs as references for multi-modal medical imaging. Validation is performed with a liver phantom imaged via SPECT-CT (single-photon emission computed tomography) and PET-CT (positron emission tomography), confirming the accuracy and reliability of the proposed approach. Additionally, promising visual results on a patient's liver are also presented.