Format

Send to

Choose Destination
MAGMA. 2017 Jun;30(3):255-264. doi: 10.1007/s10334-016-0602-z. Epub 2016 Dec 16.

Evaluation of exposure to (ultra) high static magnetic fields during activities around human MRI scanners.

Author information

1
Department of Biomedical Magnetic Resonance, H65-ZENIT, Otto-von-Guericke-University Magdeburg, Leipziger Street 44, 39120, Magdeburg, Germany. Mahsa.Fatahi@ovgu.de.
2
Laboratory of Electromagnetic Hazards, Central Institute for Labour Protection-National Res. Inst. (CIOP-PIB), Warsaw, Poland.
3
Department of Mechanical Engineering, Imperial College London, London, UK.
4
Institute for Medical Engineering, Otto-von-Guericke University, Magdeburg, Germany.
5
Department of Biomedical Magnetic Resonance, H65-ZENIT, Otto-von-Guericke-University Magdeburg, Leipziger Street 44, 39120, Magdeburg, Germany.
6
Leibniz Institute for Neurobiology, Magdeburg, Germany.
7
Center for Behavioral Brain Sciences, Magdeburg, Germany.
8
German Center for Neurodegenerative Disease, Site Magdeburg, Magdeburg, Germany.

Abstract

OBJECTIVE:

To assess the individual exposure to the static magnetic field (SMF) and the motion-induced time-varying magnetic field (TVMF) generated by activities in an inhomogeneous SMF near high and ultra-high field magnetic resonance imaging (MRI) scanners. The study provides information on the level of exposure to high and ultra-high field MRI scanners during research activities.

MATERIALS AND METHODS:

A three-axis Hall magnetometer was used to determine the SMF and TVMF around human 3- and 7-Tesla (T) MRI systems. The 7-T MRI scanner used in this study was passively shielded and the 3-T scanner was actively shielded and both were from the same manufacturer. The results were compared with the exposure restrictions given by the International Commission on Non-Ionizing Radiation Protection (ICNIRP).

RESULTS:

The recorded exposure was highly variable between individuals, although they followed the same instructions for moving near the scanners. Maximum exposure values of B = 2057 mT and dB/dt = 4347 mT/s for the 3-T scanner and B = 2890 mT, dB/dt = 3900 mT/s for 7 T were recorded. No correlation was found between reporting the MRI-related sensory effects and exceeding the reference values.

CONCLUSIONS:

According to the results of our single-center study with five subjects, violation of the ICNIRP restrictions for max B in MRI research environments was quite unlikely at 3 and 7 T. Occasions of exceeding the dB/dt limit at 3 and 7 T were almost similar (30% of 60 exposure scenarios) and highly variable among the individuals.

KEYWORDS:

Electromagnetic fields; Exposure assessment; Occupational exposure; Static magnetic field; Time-varying field

PMID:
27981395
DOI:
10.1007/s10334-016-0602-z
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Springer
Loading ...
Support Center