Wireless and batteryless two-dimensional opto-electro-mechanical positioner inside 3 T MRI scanner.

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Robotics

Background:

• MRI-guided interventions require precise positioning systems.
• Existing systems often face limitations due to wiring, power, and MRI compatibility.

Purpose of the Study:

• To develop and demonstrate a wireless, batteryless, and optically powered two-dimensional (2D) electro-mechanical positioner for use within a 3 Tesla (3T) MRI scanner.

Main Methods:

• Utilized Lorentz force actuators with coils and silicon solar cells for power and actuation.
• Constructed a 2D positioner using two rotors made of MRI-compatible materials (plastic, glass, ceramic).
• Modeled the rotor dynamics using circuit-based simulations and designed a custom coil for optimal performance at 3T.

Main Results:

• Achieved 150 RPM rotor speed and 3.4 mN·m torque (amplified to 194 mN·m), with a linear velocity of 2.2 mm/s.
• Demonstrated open-loop accuracy of 1.5 mm, verified by MR images, with stable operation and no imaging artifacts.
• Successfully controlled positioning in X and Y directions using remote laser diode and fiber optic power transmission.

Conclusions:

• This work presents the first optically powered, wireless 2D positioner for 3T MRI environments.
• The system is suitable for precise marker placement and mechanical stimulation, with potential for 5-DOF extension in MRI-guided interventions like biopsies.