title: An anatomically realistic temperature phantom for radiofrequency heating measurements.
abstract: An anthropomorphic phantom with realistic electrical properties allows for a more accurate reproduction of tissue current patterns during excitation. A temperature map can then probe the worst-case heating expected in the unperfused case. We describe an anatomically realistic human head phantom that allows rapid three-dimensional (3D) temperature mapping at 7T.
  
  
  
  The phantom was based on hand-labeled anatomical imaging data and consists of four compartments matching the corresponding human tissues in geometry and electrical properties. The increases in temperature resulting from radiofrequency excitation were measured with MR thermometry using a temperature-sensitive contrast agent (TmDOTMA(-)) validated by direct fiber optic temperature measurements.
  
  
  
  Acquisition of 3D temperature maps of the full phantom with a temperature accuracy better than 0.1°C was achieved with an isotropic resolution of 5 mm and acquisition times of 2-4 minutes.
  
  
  
  Our results demonstrate the feasibility of constructing anatomically realistic phantoms with complex geometries incorporating the ability to measure accurate temperature maps in the phantom. The anthropomorphic temperature phantom is expected to provide a useful tool for the evaluation of the heating effects of both conventional and parallel transmit pulses and help validate electromagnetic and temperature simulations.
authors.affiliation: A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA.
authors.forename: Nadine N
authors.initials: NN
authors.lastname: Graedel
authors.affiliation: A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA.|Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Polimeni
authors.affiliation: A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA.
authors.forename: Bastien
authors.initials: B
authors.lastname: Guerin
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
authors.forename: Borjan
authors.initials: B
authors.lastname: Gagoski
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bonmassar
authors.affiliation: A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA.|Harvard Medical School, Boston, Massachusetts, USA.|Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA.
authors.forename: Lawrence L
authors.initials: LL
authors.lastname: Wald
mesh_terms: D001831:Body Temperature / Q000502:physiology* / Q000528:radiation effects*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006358:Hot Temperature; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011846:Radio Waves; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013817:Thermography / Q000295:instrumentation* / Q000379:methods
keywords: MR safety; local SAR; parallel transmit; phantom; temperature estimation; thermometry