Stealth RF energy harvesting in MRI using selective shielding.

Area of Science:

• Biomedical Engineering
• Medical Imaging Physics
• Electromagnetics

Background:

• Magnetic Resonance Imaging (MRI) systems utilize powerful radiofrequency (RF) fields.
• Supplying continuous power to on-body devices during MRI scans presents a significant challenge.
• Existing methods for powering devices within MRI environments are often limited or invasive.

Purpose of the Study:

• To investigate the feasibility of using the transmit RF field in MRI as a wireless power source for near-field devices.
• To develop a method for harvesting RF energy without compromising MRI image quality or patient safety.
• To enable the use of on-body devices during MRI examinations through wireless power transfer.

Main Methods:

• RF power harvesting was achieved using a resonant coil and RF induction.
• A selective shield was designed using electromagnetic simulation to cancel RF field distortion caused by the harvester.
• The shielded harvester was bench-tested and subsequently evaluated within a 3T MRI system during standard scanning sequences.

Main Results:

• Electromagnetic simulations confirmed the effectiveness of the selective shielding concept.
• Bench tests demonstrated efficient power harvesting capabilities with the integrated shield.
• In a 3T MRI system, the selective shielding effectively minimized RF perturbations, allowing for up to 100 mW of harvested power adjacent to a phantom without degrading image quality.

Conclusions:

• Selective shielding is a viable technique for "stealthy" RF energy harvesting within MRI environments.
• This technology can provide a reliable wireless power source for on-body medical devices during MRI procedures.
• The developed method offers a promising solution for enhancing the functionality of wearable devices in advanced medical imaging.