Design and testing of an MRI-conditional six-degree-of-freedom phantom robot.

Area of Science:

• Medical Imaging
• Robotics
• Biomedical Engineering

Background:

• Motion artifacts significantly impact Magnetic Resonance Imaging (MRI) quality and research costs.
• Existing phantom robots lack the necessary degrees of freedom (DOF) to accurately simulate complex physiological motions.
• Advanced phantom systems are crucial for developing and validating motion-robust MRI techniques.

Purpose of the Study:

• To design and test a novel six-DOF MRI-conditional robot for simulating complex physiological motions.
• To evaluate the robot's performance, including positional and rotational accuracy, within an MRI environment.
• To enhance the development and validation of motion-robust imaging techniques in MRI.

Main Methods:

• Fabrication of a six-DOF robot using 3D printed components and DC stepper motors.
• Integration of a Faraday cage to mitigate electromagnetic interference from motors and electronics.
• Testing and validation of actuator functionality and MRI-conditional properties with a 3T MRI system.
• Positional and rotational accuracy assessment using a modified ISO 9283 standard.

Main Results:

• The integrated Faraday cage effectively reduced motor-generated noise to baseline MRI levels.
• Achieved positional accuracy of 0.2 mm and rotational accuracy of [-0.1°, 0.3°, -0.2°] for x, y, z axes.
• Demonstrated path accuracy with positional accuracy of 0.3 mm and rotational accuracy of [0.1°, 0.1°, 0.1°] for sample motions.

Conclusions:

• The developed six-DOF robot significantly advances the capability to simulate complex motions in MRI.
• This system provides a valuable tool for the development and validation of motion-robust MRI sequences.
• The design offers enhanced performance and accuracy for motion phantom applications in MRI research.