Abstract #4902
Calculation of 10g average SAR via inversion of the heat equation using MRI Thermometry and Thermal Property Measurements
Leeor Alon 1,2 , Gene Cho 1,2 , Leslie F. Greengard 3 , Ricardo Otazo 1,2 , Daniel K. Sodickson 1,2 , and Cem M. Deniz 1,2
1
Department of Radiology, Bernard and Irene
Schwartz Center for Biomedical Imaging, New York
University School of Medicine, New York, NY, United
States,
2
Sackler
Institute of Graduate Biomedical Sciences, New York
University School of Medicine, New York, NY, United
States,
3
Courant
Institute of Mathematical Sciences, New York University,
NY, United States
RF safety of MRI coils is often evaluated by conducting
RF heating experiments on tissue mimicking phantoms
inside the scanner room. Because of power delivery
capabilities of RF amplifiers, long RF heating durations
(>6 minutes) are required to create a temperature change
that can be accurately detected by MR thermometry
measurements. In such cases when the heating duration is
long, conversion from temperature-change to SAR is
nontrivial, since the heat-diffusion effect is prominent
and direct scaling of the temperature change with heat
capacity yields large 10g average SAR errors (~55% ,
shown as in this abstract ). In this work, a method for
3D calculation of 10g average SAR is presented via
inversion of the heat equation using high-resolution 3D
temperature maps and measured thermal properties of the
phantom. The algorithm can be used to calculate 10g
average SAR experimentally for limiting RF energy
deposition from physical coils in the scanner room with
small errors, %3.1.
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