title: Numerically simulated exposure of children and adults to pulsed gradient fields in MRI.
abstract: To determine exposure to gradient switching fields of adults and children in a magnetic resonance imaging (MRI) scanner by evaluating internal electric fields within realistic models of adult male, adult female, and child inside transverse and longitudinal gradient coils, and to compare these results with compliance guidelines.
  
  
  
  Patients inside x-, y-, and z-gradient coils were simulated using anatomically realistic models of adult male, adult female, and child. The induced electric fields were computed for 1 kHz sinusoidal current with a magnitude of 1 A in the gradient coils. Rheobase electric fields were then calculated and compared to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) 2004 and International Electrotechnical Commission (IEC) 2010 guidelines. The effect of the human body, coil type, and skin conductivity on the induced electric field was also investigated.
  
  
  
  The internal electric fields are within the first level controlled operating mode of the guidelines and range from 2.7V m-1to 4.5V m-1, except for the adult male inside the y-gradient coil (induced field reaches 5.4V m-1).The induced electric field is sensitive to the coil type (electric field in the skin of adult male: 4V m-1, 4.6V m-1, and 3.8V m-1for x-, y-, and z-gradient coils, respectively), the human body model (electric field in the skin inside y-gradient coil: 4.6V m-1, 4.2V m-1, and 3V m-1for adult male, adult female, and child, respectively), and the skin conductivity (electric field 2.35-4.29% higher for 0.1S m-1skin conductivity compared to 0.2S m-1).
  
  
  
  The y-gradient coil induced the largest fields in the patients. The highest levels of internal electric fields occurred for the adult male model. J. Magn. Reson. Imaging 2016;44:1360-1367.
authors.affiliation: Department of Information Technology (INTEC), Ghent University/iMinds, iGent, Ghent, Belgium. amine.samoudi@intec.ugent.be.
authors.forename: Amine M
authors.initials: AM
authors.lastname: Samoudi
authors.affiliation: Department of Information Technology (INTEC), Ghent University/iMinds, iGent, Ghent, Belgium.
authors.forename: Gunter
authors.initials: G
authors.lastname: Vermeeren
authors.affiliation: Department of Information Technology (INTEC), Ghent University/iMinds, iGent, Ghent, Belgium.
authors.forename: Emmeric
authors.initials: E
authors.lastname: Tanghe
authors.affiliation: Electronics and Information Systems (ELIS), Ghent University/iMinds, Ghent, Belgium.
authors.forename: Roel
authors.initials: R
authors.lastname: Van Holen
authors.affiliation: Department of Information Technology (INTEC), Ghent University/iMinds, iGent, Ghent, Belgium.
authors.forename: Luc
authors.initials: L
authors.lastname: Martens
authors.affiliation: Department of Information Technology (INTEC), Ghent University/iMinds, iGent, Ghent, Belgium.
authors.forename: Wout
authors.initials: W
authors.lastname: Josephs
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D060526:Magnetic Fields; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008954:Models, Biological; D011829:Radiation Dosage; D000069079:Radiation Exposure / Q000032:analysis* / Q000517:prevention & control*; D011835:Radiation Protection / Q000379:methods; D051598:Whole Body Imaging / Q000379:methods*; D055815:Young Adult
keywords: ICNIRP; IEC; MRI; exposure; induced electric field; peripheral nerve stimulation