Design and control of a novel hydraulically/pneumatically actuated robotic system for MRI-guided neurosurgery

MR-compatibility of materials and devices. ConvenABSTRACT tional robotic systems are not suitable for use inside the MRI scanner because they contain ferromagnetic In this paper the design of a novel modular materials and electrical circuits. These components hydraulic/pneumatic actuated tele-robotic syscause spatial distortions and impart noise to the MR tem and a new infrastructure for MRI-guided images, while conversely the magnetic field of the intervention for closed-bore MRI-guided neuroMRI system interferes with the electrical circuits. surgery are presented. Candidate neurosurgical The strong magnetic field dictates that only nonprocedures enabled by this system would ferromagnetic materials can be used for the mechaniinclude thermal ablation, radiofrequency ablacal parts. tion, deep brain stimulators, and targeted drug The major shortcoming in the use of conventional delivery. The major focus is the application of the MRI systems for neurosurgery is their reliance on predesigned MR-compatible robotic system to MRIoperative MR images. As surgery progresses and anaguided brain biopsy. Navigation and operating tomic tissue are removed or distorted, the intracranial modules were designed to undertake the alignanatomic positional relationship of the brain and surment and advancement of the surgical needle rounding s t ructures change. This is commonly respectively. The mechanical design and conreferred to as “brain shift”. Intra-operative changes trol paradigm are reported. due to tumor resection, brain swelling, and cere brospinal fluid (CSF) leakage further increase brain shift [1, 2, 3]. As these processes are unavoidable in most neurosurgical procedures, they decrease the accuracy in all surgery that is based on preoperative MR