Demonstration and Experimental Validation of Plastic-Encased Resonant Ultrasonic Piezoelectric Actuator for Magnetic Resonance Imaging-Guided Surgical Robots

We demonstrate that image distortion related issues can be partly addressed by replacing metallic nonactive motor components from a resonant ultrasonic motor for nonmetallic equivalents

Paulo A. W. G. Carvalho; Christopher J. Nycz; Katie Y. Gandomi; Gregory S. Fischer


Scholarcy highlights

  • Brachytherapy, a localized radiation-based cancer treatment, biopsies, and tumor ablation are examples of routinely performed medical procedures that require accurate positioning of a needle inside the patient
  • The confined space of the magnetic resonance imaging bore, strong magnetic fields and susceptibility to electrical noise pose challenges, ones that can be addressed by the use of MRI compatible robots
  • There was no statistical difference between baseline and the plastic motor inside the MRI when powered off
  • Results have shown that the plastic motor causes less distortion while maintaining an equivalent or better SNR
  • The maximum observed distortion decreased from 4.91 mm to 0.34 mm for the plastic motor versus the metal motor when positioned on the side of the phantom
  • Results have shown that the SNR for the plastic motor was better than its metal counterpart, despite it being often implied that a metal enclosure is required for a piezoelectric motor to shield the MRI from electrical noise
  • The demonstration that removing the metal enclosure of a piezoelectric motor that is driven by clean signals that do not contain harmonics near the Larmor frequency for the scanner decreases distortion without causing an SNR decrease paves the way for fully plastic motors

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