Design of a robotic system for MRI-guided deep brain stimulation electrode placement

Deep brain stimulation (DBS) is a technique for influencing brain function though the use of implanted electrodes. Direct magnetic resonance (MR) image guidance during DBS insertion would provide many benefits; most significantly, interventional MRI can be used for planning, monitoring of tissue deformation, real-time visualization of insertion, and confirmation of placement. The accuracy of standard stereotactic insertion is limited by registration errors and brain movement during surgery. With real-time acquisition of highresolution MR images during insertion, probe placement can be confirmed intra-operatively. Direct MR guidance has not yet taken hold because it is often confounded by a number of issues including: MR-compatibility of existing stereotactic surgery equipment and patient access in the scanner bore. The high resolution images required for neurosurgical planning and guidance require high-field MR (1.5-3T); thus, any system must be capable of working within the constraints of a closed, longbore diagnostic magnet. Currently, no technological solution exists to assist MRI guided neurosurgical interventions in an accurate, simple, and economical manner.We present the design of a robotic assistant system that overcomes these difficulties and promises safe and reliable electrode placement in the brain inside closed high-field MRI scanners. The robot performs the insertion under real-time 3T MR image guidance. This paper described analysis of the workspace requirements, MR compatibility evaluation, and mechanism design.