Design and analysis of magnetic resonance compatibility of ultrasonic motor in surgical robot

The operation and mounting of ultrasonic (US) motor have significant effect on MR-compatibility of surgical robot. This paper presented the mathematic model for calculating signal-noise ratio (SNR). The tests of MR-compatibility of single-US motor with parallel and perpendicular mounting separately and multi-US motors with mixed mounting were performed under Philips 3T scanner. The MR images and SNR of the above experimental tests were obtained. The results and their analysis show preliminarily that the quality of MR images in parallel mounting was better than perpendicular mounting; a sufficiently large distance between US motor and isocenter of MR scanner is necessary to avoid artifacts and noise; the design of automatic turning/matching device can significantly improve the MR-compatibility of US motors. Section 4 gives concluding remarks, which present suggestions in many respects for improving MR-compatibility but appear to be very difficult to be summarized concisely.