A system for MRI-guided prostate interventions

Numerous studies have demonstrated the efficacy of image-guided needle-based therapy and biopsy in the management of prostate cancer. Magnetic Resonance Imaging (MRI) is an ideal modality for guiding and monitoring such interventions due to its excellent visualization of the prostate, its sub-structure and surrounding tissues. However, the accuracy of needle placement is limited by image fidelity, needle template guides, needle deflection and tissue deformation. We present a preliminary study of the key sources of needle placement error in actual clinical cases. To address these errors, we have designed a comprehensive robotic assistant system with the following features: high-fidelity MRI imaging, advanced planning and targeting with statistical anatomical atlases and multi-parametric imaging, improved navigation based on direct image feedback, and steady needle placement with a robotic manipulator. The prostate biopsy and brachytherapy procedures are to be performed entirely inside a 3T closed-bore MRI scanner. We present a detailed design of the robotic manipulator and associated planning and targeting systems.