title: [A 3D FEM model for calculation of electromagnetic fields in transmagnetic stimulation].
abstract: We developed a realistic finite elements method (FEM) model of the brain for the calculation of electromagnetic fields in transcranial magnetic stimulation (TMS). A focal butterfly stimulation coil was X-rayed, parameterized, and modeled. The magnetic field components of the TMS coil were calculated and compared for validation to pointwise measurements of the magnetic fields with a Hall sensor. We found a mean deviation of 7.4% at an axial distance of 20 mm to the coil. A 3D brain model with the biological tissues of white and gray matter, bone, and cerebrospinal fluid was developed. At a current sweep of 1000 A in 120 microseconds, the maximum induced current density in gray matter was 177 mA/m2 and the strongest electric field gradient covered an area of 40 mm x 53 mm.
authors.affiliation: Department of Biomedical Engineering, University of Applied Sciences, Jena, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Seilwinder
authors.forename: T
authors.initials: T
authors.lastname: Kammer
authors.forename: W
authors.initials: W
authors.lastname: Andrä
authors.forename: M E
authors.initials: ME
authors.lastname: Bellemann
mesh_terms: D001921:Brain / Q000033:anatomy & histology / Q000528:radiation effects*; D003198:Computer Simulation; D004574:Electromagnetic Fields; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008280:Magnetics / Q000627:therapeutic use*; D008432:Mathematical Computing; D019047:Phantoms, Imaging