Measurement of SAR-induced temperature increase in a phantom and in vivo with comparison to numerical simulation

• Published in: Magnetic resonance in medicine Vol. 71; no. 5; pp. 1923 - 1931
• Main Authors: Oh, Sukhoon, Ryu, Yeun-Chul, Carluccio, Giuseppe, Sica, Christopher T., Collins, Christopher M.
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01-05-2014; Wiley Subscription Services, Inc
• Subjects: Absorption, Radiation; Body Temperature - physiology; Body Temperature - radiation effects; Computer Simulation; Forearm - physiology; Forearm - radiation effects; Humans; Magnetic Fields; Magnetic Resonance Imaging - methods; Models, Biological; MRI; PRF; safety; SAR; simulation; Temperature; Thermography - methods; temperature; MRI; PRF; SAR; safety; simulation
• ISSN: 0740-3194; 1522-2594
• DOI: 10.1002/mrm.24820

Purpose
To compare numerically simulated and experimentally measured temperature increase due to specific energy absorption rate from radiofrequency fields.
Methods
Temperature increase induced in both a phantom and in the human forearm when driving an adjacent circular surface coil was mapped using the proton resonance frequency shift technique of magnetic resonance thermography. The phantom and forearm were also modeled from magnetic resonance image data, and both specific energy absorption rate and temperature change as induced by the same coil were simulated numerically.
Results
The simulated and measured temperature increase distributions were generally in good agreement for the phantom. The relative distributions for the human forearm were very similar, with the simulations giving maximum temperature increase about 25% higher than measured.
Conclusion
Although a number of parameters and uncertainties are involved, it should be possible to use numerical simulations to produce reasonably accurate and conservative estimates of temperature distribution to ensure safety in magnetic resonance imaging. Magn Reson Med 71:1923–1931, 2014. © 2013 Wiley Periodicals, Inc.