Method and system for estimating the specific absorption rate of a tissue region prior to a magnetic resonance imaging scan

A system for determining a specific absorption rate of a tissue region, the system comprising:

• a radiation source configured to radiate the tissue region with a plurality of pulses, wherein the tissue region emits thermoacoustic signals responsive to the pulses;
• at least one ultrasonic transducer configured to receive the thermoacoustic signals;
• and
• one or more processors configured to calculate a temperature rise of the tissue region based on the plurality of received thermoacoustic signals, scale the temperature rise to estimate a temperature rise of the tissue region resulting from an MR imaging scan, and estimate the specific absorption rate of the tissue region based on the estimated temperature rise.

A non-transitory computer-readable medium having stored thereon a computer program comprising computer program code, the computer program code executable by one or more processors to perform a method comprising:

• calculating a temperature rise of a tissue region based on received thermoacoustic signals;
• scaling the temperature rise to estimate a temperature rise of the tissue region resulting from an MR imaging scan;
• and
• estimating a specific absorption rate of the tissue region based on the estimated temperature rise.

A method for calibrating a magnetic resonance (MR) imaging scanner, comprising calculating a temperature rise of a tissue region based on a plurality of received thermoacoustic signals emitted by the tissue region in response to the tissue region being radiated by a plurality of short radio frequency (RF) pulses:

• scaling the temperature rise to estimate a temperature rise of the tissue region resulting from an MR imaging scan:
• estimating the specific absorption rate of the tissue region based on the estimated temperature rise;
• and
• if the specific absorption rate is outside of a defined range, adjusting at east one parameter of the MR imaging scanner.

A method for generating a prediction algorithm to estimate the specific absorption rate of a tissue region, the method comprising:

• (a) constructing a physical phantom representing characteristics of the tissue region;
• (b) generating a numeral model of the physical phantom;
• (c) calculating a prediction algorithm of the specific absorption rate of the physical phantom and estimating the specific absorption rate of the physical phantom using the prediction algorithm;
• (d) radiating the physical phantom with a plurality of radio frequency (RF) pulses and directly measuring the specific absorption rate of the physical phantom;
• (e) comparing the estimated specific absorption rate to the directly measured specific absorption rate;
• (f) if the estimation of the specific absorption rate is not accurate, updating the prediction algorithm using the directly measured specific absorption rate and repeating steps (d) and (e);
• and
• (g) if the estimation of the specific absorption rate is accurate, storing the prediction algorithm in a database.

A method for estimating a specific absorption rate of a tissue region prior to performing a magnetic resonance (MR) imaging scan on the tissue region, the method comprising;

• determining one or more characteristics of the tissue region;
• selecting a specific absorption rate prediction algorithm based on the determined one or more characteristics of the tissue region from a database of validated specific absorption rate prediction algorithms;
• and
• estimating the specific absorption rate of the tissue region using the selected specific absorption rate prediction algorithm.

A method for calibrating a magnetic resonance (MR) imaging scanner, comprising:

• determining one or more characteristics of the tissue region;
• selecting a specific absorption rate prediction algorithm based on the determined one or more characteristics from a database of validated specific absorption rate prediction algorithms;
• estimating the specific absorption rate of the tissue region using the selected specific absorption rate prediction algorithm;
• and
• if the estimated specific absorption rate is outside of a defined range, adjusting at least one parameter of the MR imaging scanner.