MRI Compatible Robotics:

Magnetic Resonance Imaging (MRI) is an excellent imaging modality for many conditions, but to date there has been limited success in harnessing this modality for the guidance of interventional procedures. MRI is an ideal interventional guidance modality: it provides near real-time high-resolution images at arbitrary orientations and is able to monitor therapeutic agents, surgical tools, biomechanical tissue properties, and physiological function. At the same time, MRI poses formidable engineering challenges by severely limited access to the patient and high magnetic field that prevents the use of conventional materials and electronic equipment. We have developed: a modular MRI robot control system, approaches to actuating piezoelectric motors, optical force sensors, in-bore teleoperation, and surgical systems for stereotactic neurosurgery and percutaneous prostate cancer interventions.
MRI Robot for Precision Deep Brain Stimulation Probe Placement

MRI Compatible Neurosurgery Robot
Robotic Deep Brain Stimulation for Parkinson's Disease Treatment
Direct MR image guidance during deep brain stimulation (DBS) insertion offers 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 high-resolution MR images during insertion, probe placement can be confirmed intra-operatively. Direct MR guidance has not 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, long-bore diagnostic magnet. Currently, no technological solution exists to assist MRI guided neurosurgical interventions in an accurate, simple, and economical manner. The objective of our research is to make conventional diagnostic closed high-field MRI scanners available for guiding deep brain stimulation electrode placement interventions for treatment of Parkinson's Disease and other neurological disorders including severe depression and Alzheimer's Disease. Our approach is to employ an MRI-compatible robotic assistant for guiding DBS electrode insertion under direct, real-time MR image guidance. The system will allow interactive probe alignment under real-time imaging in standard diagnostic high-field MR scanners. Use of a robotic assistant will minimize the potential for human error and mis-registration associated with the current procedure and will better address the practical issues of operating in an MR scanner bore.
Piezoelectrically Actuated MRI-Compatible Robot for Prostate Interventions
MRI has potential to be a superior medical imaging modality for guiding and monitoring prostatic interventions. MRI can provide high-quality 3D visualization of prostate and surrounding tissue. However, the benefits can not be readily harnessed for interventional procedures due to difficulties that surround the use of high-field (1.5T or greater). The strong magnetic field prevents the use of conventional mechatronics and the confined physical space makes it extremely challenging to access the patient. We have designed a robotic assistant system that overcomes these difficulties and promises safe and reliable intra-prostatic needle placement inside closed high-field MRI scanners.
Modular MRI Compatible Robot Controller

MRI Compatible Robot Controller
The unavailability of robot control interfaces that are compatible with the MRI environment has severely limited the ability to do research in the field. The high cost of entry into MRI robotics has been primarily due to the need for each researcher to develop and evaluate their control system in the scanner. We have developed an MRI compatible robot controller that sits in the scanner room without interfering with scanner imaging. The controller is modular and allows many different inputs and output and communicates to a high level planning and navigation software workstation through fiber optic connections.
Development and Evaluation of MRI-Compatible Actuators
Traditional actuators are often contraindicated by the strong magnetic and electric fields present in the MRI scanner bore. Further, it is critical that the devices not introduce noise or distortion into the acquired images. We are evaluating different actuator schemes including pneumatics and piezoelectric actuators. We are investigating ways of optimizing piezoelectric motors for MR-compatibility and developing high-accuracy pneumatic control systems.
Development and Evaluation of MRI-Compatible Sensors
Traditional sensors in robotics include force and positioning sensing. However, off-the-shelf sensors are not suiatable for use in MRI due to the potential for image degradation, malfunction, or safety issues. We are evaluating and developing sensors to be used in the MR environment. The current focus is on optical techniques for force and position sensing that do not compromise image quality and will allow for haptic feedback during MRI-guided interventions.
Pneumatically Operated MRI Robot for Transperineal Prostate Diagnosis and Treatment

MRI Compatible Needle Placement Robot
MRI has potential to be a superior medical imaging modality for guiding and monitoring prostatic interventions. MRI can provide high-quality 3D visualization of prostate and surrounding tissue. However, the benefits can not be readily harnessed for interventional procedures due to difficulties that surround the use of high-field (1.5T or greater). The strong magnetic field prevents the use of conventional mechatronics and the confined physical space makes it extremely challenging to access the patient. We have designed a robotic assistant system that overcomes these difficulties and promises safe and reliable intra-prostatic needle placement inside closed high-field MRI scanners.
Clinically Focused MRI Robot Control Architecture

MRI Robot Controller Architecture
We have developed a clinically focused robot control architecture to support our MRI-compatible robotic systems. The work includes custom hardware, communication protocols, and user interfaces. Safety and reliability are incorporated while ensuring a clinically appropriate workflow. The system is configured for clinical trials with the MRI-guided Prostate Biopsy and Brachytherapy robot.