title: A method for safety testing of radiofrequency/microwave-emitting devices using MRI.
abstract: OBJECTIVE
  Strict regulations are imposed on the amount of radiofrequency (RF) energy that devices can emit to prevent excessive deposition of RF energy into the body. In this study, we investigated the application of MR temperature mapping and 10-g average specific absorption rate (SAR) computation for safety evaluation of RF-emitting devices.
  
  
  METHODS
  Quantification of the RF power deposition was shown for an MRI-compatible dipole antenna and a non-MRI-compatible mobile phone via phantom temperature change measurements. Validation of the MR temperature mapping method was demonstrated by comparison with physical temperature measurements and electromagnetic field simulations. MR temperature measurements alongside physical property measurements were used to reconstruct 10-g average SAR.
  
  
  RESULTS
  The maximum temperature change for a dipole antenna and the maximum 10-g average SAR were 1.83°C and 12.4 W/kg, respectively, for simulations and 1.73°C and 11.9 W/kg, respectively, for experiments. The difference between MR and probe thermometry was <0.15°C. The maximum temperature change and the maximum 10-g average SAR for a cell phone radiating at maximum output for 15 min was 1.7°C and 0.54 W/kg, respectively.
  
  
  CONCLUSIONS
  Information acquired using MR temperature mapping and thermal property measurements can assess RF/microwave safety with high resolution and fidelity.
authors.affiliation: The Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University, School of Medicine, New York, New York, USA.|Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York, USA.|NYU WIRELESS, Polytechnic Institute of New York University, Brooklyn, New York, USA.|RF Test Labs, Inc., New York, New York, USA.
authors.forename: Leeor
authors.initials: L
authors.lastname: Alon
authors.affiliation: The Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University, School of Medicine, New York, New York, USA.|Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York, USA.|RF Test Labs, Inc., New York, New York, USA.
authors.forename: Gene Y
authors.initials: GY
authors.lastname: Cho
authors.forename: Xing
authors.initials: X
authors.lastname: Yang
authors.affiliation: The Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University, School of Medicine, New York, New York, USA.|Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York, USA.|NYU WIRELESS, Polytechnic Institute of New York University, Brooklyn, New York, USA.
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Sodickson
authors.affiliation: The Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University, School of Medicine, New York, New York, USA.|Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York, USA.|NYU WIRELESS, Polytechnic Institute of New York University, Brooklyn, New York, USA.|RF Test Labs, Inc., New York, New York, USA.
authors.forename: Cem M
authors.initials: CM
authors.lastname: Deniz
mesh_terms: D065638:Absorption, Radiation; D040421:Cell Phone; D003198:Computer Simulation; D004574:Electromagnetic Fields; D006257:Head / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008872:Microwaves; D008954:Models, Biological; D019047:Phantoms, Imaging; D011846:Radio Waves; D013672:Technology / Q000295:instrumentation / Q000592:standards
keywords: Local SAR; RF Simulations; RF dosimetry; RF power deposition; SAR; microwave dosimetry