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Int J Environ Res Public Health. 2018 Jun 21;15(7). pii: E1298. doi: 10.3390/ijerph15071298.

dB/dt Evaluation in MRI Sites: Is ICNIRP Threshold Limit (for Workers) Exceeded?

Author information

1
Department of BIOMORF, University of Messina, Via Consolare Valeria, 98168 Messina, Italy. gacri@unime.it.
2
School on Medical Physic, University of Messina, Via Consolare Valeria, 98168 Messina, Italy. patrizia.inferrera@gmail.com.
3
Department of BIOMORF, University of Messina, Via Consolare Valeria, 98168 Messina, Italy. ldenaro@unime.it.
4
Department of BIOMORF, University of Messina, Via Consolare Valeria, 98168 Messina, Italy. sansotta@unime.it.
5
Department of BIOMORF, University of Messina, Via Consolare Valeria, 98168 Messina, Italy. eruello@unime.it.
6
IRCCS Centro Neurolesi "Bonino-Pulejo", Via Palermo, C.da Casazza, 98123 Messina, Italy. carmelo.anfuso@irccsme.it.
7
Department of BIOMORF, University of Messina, Via Consolare Valeria, 98168 Messina, Italy. fmsalmeri@unime.it.
8
IEMEST (PA), Fondazione Potito (CB), FISMECO (RM), Via G. Donati, 00159 Roma, Italy. g.garreffa@gmail.com.
9
Department of P.A.S.S.I., University of Messina, Consolare Valeria, 98168 Messina, Italy. vermigli@unime.it.
10
Department of BIOMORF, University of Messina, Via Consolare Valeria, 98168 Messina, Italy. btestagrossa@unime.it.

Abstract

The Directive 2013/35/EU establishes standards for workers exposed to static and time varying magnetic fields. These limits are based on ICNIRP guidelines expressed in terms of the electric field induced in the body. The complexity of this measurement led to theoretical models being developed. In this study, the experimental evaluation included varying magnetic field exposures for two classes of MRI workers. The measurements are conducted on four different MRI Systems including one 0.35 T, two 1.5 T, and one 3.0 T. Pocket magnetic dosimeters were used and it was carried out during routine conditions, emergency conditions, and cold-head maintenance/substitution. The acquired data has been processed and the corresponding dB/dt curves have been computed as the first time derivative of the dataset. The weighted peak approach was also implemented for the compliance assessment with regulatory limits. The dB/dt peak values have been compared with the reference level (RL) proposed by ICNIRP. The results show that the RL always exceeds during measurements on the 3.0 T scanner and sometimes on 1.5 T. In light of the foregoing, the diffusion of ultra-high field MRI scanners involves the introduction of behavioral rules that could be more useful than a numerical action level.

KEYWORDS:

MRI safety; MRI workers exposure; static magnetic field; time-varying magnetic field

PMID:
29933587
PMCID:
PMC6068997
DOI:
10.3390/ijerph15071298
[Indexed for MEDLINE]
Free PMC Article

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