The global site of the UK's leading magazine for automation, motion engineering and power transmission
26 November, 2021

Ceramic motors will allow surgeons to operate in MRI scanners

21 February, 2008

An international team of engineers and researchers has developed a surgical robot that incorporates non-magnetic ceramic motors that allow it to be used safely in the strong magnetic field of an MRI (magnetic resonance imaging) system. The neuroArm robot will allow surgeons to perform precision surgery on patients while they are in an MRI scanner, which can be used to view the progress of the operation in real time.

neuroArm robot

Until now, the magnetic nature of conventional electric motors and their use of metal components has prevented surgeons from conducting operations within MRI machines. The new arm, which is formed from plastics, titanium and other non-magnetic materials, can be used safely in scanners to perform intricate surgery to accuracies of 0.01mm. The arm, which can be used singly or in pairs, also provides tactile feedback to the remotely located surgeon. Initially, the main application is likely to be brain surgery.

The C$27m neuroArm project was started in 2001 by Dr Garnette Sutherland, professor of neurosurgery at the University of Calgary in Canada. The development team includes the robotics division of MacDonald Dettwiler and Associates, which developed the robot arms carried on board the Space Shuttle.

The neuroArm robot incorporates 16 ultrasonic piezoelectric motors developed by the US-based Johnson Medtech division of the Hong Kong motor manufacturer, Johnson Electric. The non-magnetic motors are used in the armís six rotary joints. Their precision allows the surgeons to operate to accuracies similar to the width of a human hair, compared to the 3mm accuracy that the best surgeons can achieve, unaided. According to Sutherland, this will allow surgery to move from the organ to the cell level.

Another attraction of the neuroArm is that it eliminates the natural tremors in a surgeonís arm and hand movements.

Johnson Nanomotion motors

The ceramic motors (shown above with their controller), developed by Johnsonís Nanomotion subsidiary, are based on piezo crystals that vibrate at about 40kHz. These vibrations are harnessed to rotate ceramic rings. The motors draw around 100mA Ė too small to affect the operation of the MRI scanner.

The neuroArm is now entering clinical trials and will need to be approved by regulatory authorities before it can be used commercially.

  • To view a digital copy of the latest issue of Drives & Controls, click here.

    To visit the digital library of past issues, click here

    To subscribe to the magazine, click here



Drives Show 2022The next Drives & Controls Exhibition and Conference will take place in Birmingham, UK, from 5-7 April, 2022. For more information on the event, visit the Show Web site


"Do you think that robots create or destroy jobs?"



Most Read Articles