Real-time, High-dynamic Range RF Power Monitor for MRI/MRS

Case ID:

C11463

C11463: Real-Time High Dynamic Range RF Power Monitor

Novelty:

This device is a reduced-to-practice 6-channel MRI-compatible RF monitor that can operate up to 400MHz and accurately measure RF power over the full dynamic range and duty cycles of clinical and research MRI scanners, NMR instruments, and RF transmitters.

Value Proposition:

Measurement of RF power delivery, and deposition in the body (the specific absorption rate, SAR) during human MRI scanning is critical in complying with FDA regulations and ensuring patient safety. Accurate RF power measurements are also required for testing the safety of implanted devices and leads exposed to RF during MRI. Currently, there are no existing commercial RF power monitoring systems that can provide accurate measures of RF power over the dynamic range and duty cycle routinely encountered in MRI. This new technology provides a real-time, high-dynamic range RF power monitor that allows for accurate measurements of RF power deposition-essential for independent verification of RF exposure and MRI safety. Advantages of the current invention include:

• Dynamic range beyond commercially available power meters (~90dB) .

• Multiple low loss (~0.1dB) channels can measure at multiple locations simultaneously (no interference with scanner operation .

• Accurately handles pulse duty cycles from CW to 0.001 or less (1 pulse/many seconds). .

• Also suitable for RF power measurement in other applications (radio, radar, telecommunications systems etc)

Technical Details:

Johns Hopkins researchers have developed a device to measure RF power over a wide range of MRI operating conditions. The prototype RF power meter has 6 channels, a high sample rate (5 µs), is linear over specified duty cycles and pulse types, and can measure RF exposure in real-time independent of the scanner. It provides significantly more accurate measures of RF power than RF monitors embedded in several common commercial MRI scanners, and several commercial RF power meters operating in the same RF range. The multi-channel capability enables measurement of RF at multiple points in the transmit chain for further analysis of power loss and SAR. The invention enables more precise monitoring for regulatory compliance, SAR dosimetry, setting RF exposure levels for testing peripherals and implants.

Looking for Partners:

To develop and commercialize the technology as a highly accurate RF power monitor and meter suitable for measuring RF power delivery over an extraordinary range of operating conditions.

Stage of Development:

Prototype built and tested

Data Availability:

Reduced-to-practice in MRI scanners in a clinical setting

Publications/Associated Cases:

Med Phys. 2012 May;39(5):2334-41