title: Heat equation inversion framework for average SAR calculation from magnetic resonance thermal imaging.
abstract: Deposition of radiofrequency (RF) energy can be quantified via electric field or temperature change measurements. Magnetic resonance imaging has been used as a tool to measure three dimensional small temperature changes associated with RF radiation exposure. When duration of RF exposure is long, conversion from temperature change to specific absorption rate (SAR) is nontrivial due to prominent heat-diffusion and conduction effects. In this work, we demonstrated a method for calculation of SAR via an inversion of the heat equation including heat-diffusion and conduction effects. This method utilizes high-resolution three dimensional magnetic resonance temperature images and measured thermal properties of the phantom to achieve accurate calculation of SAR. Accuracy of the proposed method was analyzed with respect to operating frequency of a dipole antenna and parameters used in heat equation inversion. Bioelectromagnetics. 37:493-503, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York City, New York. leeor.alon@nyumc.org.|The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York City, New York. leeor.alon@nyumc.org.|NYU WIRELESS, Polytechnic Institute of New York University, Brooklyn, New York. leeor.alon@nyumc.org.|RF Test Labs, New York City, New York. leeor.alon@nyumc.org.
authors.forename: Leeor
authors.initials: L
authors.lastname: Alon
authors.affiliation: Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York City, New York.|The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York City, New York.|NYU WIRELESS, Polytechnic Institute of New York University, Brooklyn, New York.
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Sodickson
authors.affiliation: Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York City, New York.|The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York City, New York.|NYU WIRELESS, Polytechnic Institute of New York University, Brooklyn, New York.|RF Test Labs, New York City, New York.
authors.forename: Cem M
authors.initials: CM
authors.lastname: Deniz
mesh_terms: D065638:Absorption, Radiation; D004058:Diffusion; D006358:Hot Temperature; D008279:Magnetic Resonance Imaging; D019047:Phantoms, Imaging; D011846:Radio Waves
keywords: MRI; dosimetry; exposure assessment; specific absorption rate; temperature mapping