Background: In magnetic resonance (MR) image-guided microwave thermocoagulation of liver tumors, the choice of the optimal puncture route is an important and time-consuming process. To assist this process, we have developed a motorized MR-compatible manipulator.
Methods: The manipulator consists of a passive end effecter with 2 degrees-of-freedom (DOF) rotation and active base stages with 3 ultrasonic motors. It automatically chases the preset target point with synergetic remote-center-of-motion (RCM) control. A mechanical torque limiter and an electrical shutdown switch were added for patient safety.
Results: The manipulator was used for this procedure in 15 cases and successfully utilized to treat liver tumors in various locations. Thoracoscopic assistance was combined with the manipulator in 6 cases. No complications were experienced.
Conclusions: The manipulator was found to be very effective for assisting MR-guided microwave coagulation of liver tumors.