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EMF exposure variation among MRI sequences from pediatric examination protocols

Frankel, Jennifer; Hansson Mild, Kjell; Olsrud, Johan LU and Wilén, Jonna (2019) In Bioelectromagnetics 40(1). p.3-15
Abstract

The magnetic resonance imaging (MRI) exposure environment is unique due to the mixture and intensity of magnetic fields involved. Current safety regulations are based on well-known acute effects of heating and neuroexcitation while the scientific grounds for possible long-term effects from MRI exposure are lacking. Epidemiological research requires careful exposure characterization, and as a first step toward improved exposure assessment we set out to characterize the MRI-patient exposure environment. Seven MRI sequences were run on a 3-Tesla scanner while the radiofrequency and gradient magnetic fields were measured inside the scanner bore. The sequences were compared in terms of 14 different exposure parameters. To study... (More)

The magnetic resonance imaging (MRI) exposure environment is unique due to the mixture and intensity of magnetic fields involved. Current safety regulations are based on well-known acute effects of heating and neuroexcitation while the scientific grounds for possible long-term effects from MRI exposure are lacking. Epidemiological research requires careful exposure characterization, and as a first step toward improved exposure assessment we set out to characterize the MRI-patient exposure environment. Seven MRI sequences were run on a 3-Tesla scanner while the radiofrequency and gradient magnetic fields were measured inside the scanner bore. The sequences were compared in terms of 14 different exposure parameters. To study within–sequence variability, we varied sequence settings such as flip angle and slice thickness one at a time, to determine if they had any impact on exposure endpoints. There were significant differences between two or more sequences for all fourteen exposure parameters. Within–sequence differences were up to 60% of the corresponding between-sequence differences, and a 5–8 fold exposure increase was caused by variations in flip angle, slice spacing, and field of view. MRI exposure is therefore not only sequence-specific but also patient- and examination occurrence-specific, a complexity that requires careful consideration for an MRI exposure assessment in epidemiological studies to be meaningful. Bioelectromagnetics. 40:3–15, 2019.

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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
children, electromagnetic field, epidemiology, exposure assessment, radiofrequency
in
Bioelectromagnetics
volume
40
issue
1
pages
13 pages
publisher
John Wiley & Sons
external identifiers
  • scopus:85057846232
ISSN
0197-8462
DOI
10.1002/bem.22159
language
English
LU publication?
no
id
13ecb8ad-a67c-4033-8daa-54409eddfe25
date added to LUP
2019-01-07 15:48:44
date last changed
2019-01-07 15:48:44
@article{13ecb8ad-a67c-4033-8daa-54409eddfe25,
  abstract     = {<p>The magnetic resonance imaging (MRI) exposure environment is unique due to the mixture and intensity of magnetic fields involved. Current safety regulations are based on well-known acute effects of heating and neuroexcitation while the scientific grounds for possible long-term effects from MRI exposure are lacking. Epidemiological research requires careful exposure characterization, and as a first step toward improved exposure assessment we set out to characterize the MRI-patient exposure environment. Seven MRI sequences were run on a 3-Tesla scanner while the radiofrequency and gradient magnetic fields were measured inside the scanner bore. The sequences were compared in terms of 14 different exposure parameters. To study within–sequence variability, we varied sequence settings such as flip angle and slice thickness one at a time, to determine if they had any impact on exposure endpoints. There were significant differences between two or more sequences for all fourteen exposure parameters. Within–sequence differences were up to 60% of the corresponding between-sequence differences, and a 5–8 fold exposure increase was caused by variations in flip angle, slice spacing, and field of view. MRI exposure is therefore not only sequence-specific but also patient- and examination occurrence-specific, a complexity that requires careful consideration for an MRI exposure assessment in epidemiological studies to be meaningful. Bioelectromagnetics. 40:3–15, 2019.</p>},
  author       = {Frankel, Jennifer and Hansson Mild, Kjell and Olsrud, Johan and Wilén, Jonna},
  issn         = {0197-8462},
  keyword      = {children,electromagnetic field,epidemiology,exposure assessment,radiofrequency},
  language     = {eng},
  number       = {1},
  pages        = {3--15},
  publisher    = {John Wiley & Sons},
  series       = {Bioelectromagnetics},
  title        = {EMF exposure variation among MRI sequences from pediatric examination protocols},
  url          = {http://dx.doi.org/10.1002/bem.22159},
  volume       = {40},
  year         = {2019},
}