Integrating In-Bore Navigation Frames With Continuum Robot for MRI-Guided Steerable Laser Ablation of Brain Tumor

Current MR-conditional neurosurgical robotic systems face challenges in bulky navigation setup and limited distal dexterity. To address these, we introduce navigation frames consisting of a compact spherical stereotactic frame and a fixture frame, and a system for MRI-guided laser interstitial thermal therapy (LITT) of brain tumors integrating the navigation frames and a steerable robotic laser manipulator. The novel navigation frames enable in-bore stereotactic targeting through multiple burr holes with a single registration procedure and 3-degree-of-freedom pivoting about each burr hole, while simultaneously support the actuator-equipped manipulator across a large workspace. Kinematic modeling and design optimization were performed for the navigation components to achieve Pareto balance between large laser coverage and sufficient stiffness for the manipulator support. The unique setting enables in the clinical workflow intuitive navigation frames adjustment for stereotactic targeting and iterative laser tip steering to adapt to targeting error and various tumor geometries. Experiments demonstrate high tip positioning accuracy (RMSE 1.45 mm), minimal MR imaging interference ( $\lt 1.71\%~\Delta $ SNR, <0.71 mm distortion), and precise MRI-guided tip steering (RMSE 2.1 mm). Compared to existing MRI-guided neurosurgical systems, our system offers practical and accurate navigation, distal robot dexterity, and minimal MR image disruption, potentially improving clinical LITT outcomes and facilitating autonomous MRI-guided ablation strategies.