Parallel Driven Robot for MRI-Guided Prostate Therapy

Robot-assisted surgery is recognized as an effective approach for prostate cancer diagnosis and treatment. The benefits of this approach include its high targeting precision, shorter operation time, and fewer operative wounds to the patient. This article introduces a robot for transperineal prostate interventions, offering a compact design for the confined magnetic resonance (MR) scanner bore. With four actuated degrees of freedom (DoF), the position and orientation of the coaxial guide are managed by four linear actuators, and the needle insertion is performed manually, allowing the needle tip to move within a two-DoF Cartesian plane and rotate around two axes. All the actuators are driven by pneumatic power, with the valves placed outside the MR room. The combination working of four actuators and the manual insertion provides an adequate workspace for the needle tip that can cover the whole prostate with various orientations. The mechanism modeling and kinematic analysis were introduced, and the control system was presented. The open-air test shows that the robot can achieve a positioning accuracy of 0.77 mm. Magnetic resonance imaging (MRI) compatibility was evaluated under a 3T MRI scanner, showing that the signal-to-noise ratio reduction caused by the presence of the robot was less than 5%.