title: The use of MR B+1 imaging for validation of FDTD electromagnetic simulations of human anatomies.
abstract: In this study, MR B(+)(1) imaging is employed to experimentally verify the validity of FDTD simulations of electromagnetic field patterns in human anatomies. Measurements and FDTD simulations of the B(+)(1) field induced by a 3 T MR body coil in a human corpse were performed. It was found that MR B(+)(1) imaging is a sensitive method to measure the radiofrequency (RF) magnetic field inside a human anatomy with a precision of approximately 3.5%. A good correlation was found between the B(+)(1) measurements and FDTD simulations. The measured B(+)(1) pattern for a human pelvis consisted of a global, diagonal modulation pattern plus local B(+)(1) heterogeneties. It is believed that these local B(+)(1) field variations are the result of peaks in the induced electric currents, which could not be resolved by the FDTD simulations on a 5 mm(3) simulation grid. The findings from this study demonstrate that B(+)(1) imaging is a valuable experimental technique to gain more knowledge about the dielectric interaction of RF fields with the human anatomy.
authors.affiliation: Department of Radiotherapy, University Medical Center Utrecht, PO Box 85500, HP Q.00.118 3508 GA Utrecht, The Netherlands. c.a.t.vandenberg@azu.nl
authors.forename: Cornelis A T
authors.initials: CA
authors.lastname: Van den Berg
authors.forename: Lambertus W
authors.initials: LW
authors.lastname: Bartels
authors.forename: Bob
authors.initials: B
authors.lastname: van den Bergen
authors.forename: Hugo
authors.initials: H
authors.lastname: Kroeze
authors.forename: Astrid A C
authors.initials: AA
authors.lastname: de Leeuw
authors.forename: Jeroen B
authors.initials: JB
authors.lastname: Van de Kamer
authors.forename: Jan J W
authors.initials: JJ
authors.lastname: Lagendijk
mesh_terms: D003198:Computer Simulation; D004574:Electromagnetic Fields; D055590:Electromagnetic Phenomena; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009010:Monte Carlo Method; D009716:Numerical Analysis, Computer-Assisted; D019047:Phantoms, Imaging; D011846:Radio Waves; D011880:Radiotherapy Planning, Computer-Assisted; D013997:Time Factors