Compatibility of US motors for development of MRI-guided surgical robot

US (Ultrasonic) motors have potential applications as MR-compatible actuators for MRI-guided surgical robots. MR compatibility test of US motors (Shinsei USR 30 and USR 60) were performed in 3T MRI scanner under baseline, power-off, power-on, and moving configurations with mounting orientations parallel and perpendicular to the longitudinal bore axis. Normalized SNR was used to calculate the MR compatibility of US motors. The results show that the safe distances for USR 30 and USR 60 from the isocenter are 15cm and 20cm, respectively. Moving configuration decreased the normalized SNR by 15%-25%. In the same mounting orientation, three imaging sequences performed differently in terms of quality of MR images. To conclude, the Shinsei USR 30 and USR 60 are suitable for providing actuation of MRI-guided surgical robot during real-time imaging, and the MR compatibility could be improved by selecting suitable safe distance and mounting orientation.