Occupational exposure to electromagnetic fields in magnetic resonance environment: basic aspects and review of exposure assessment approaches

Abstract

The purpose of this review is to make a contribution to build a comprehensive knowledge of the main aspects related to the occupational exposure to electromagnetic fields (EMFs) in magnetic resonance imaging (MRI) environments. Information has been obtained from original research papers published in international peer-reviewed journals in the English language and from documents published by governmental bodies and authorities. An overview of the occupational exposure scenarios to static magnetic fields, motion-induced, time-varying magnetic fields, and gradient and radiofrequency fields is provided, together with a summary of the relevant regulation for limiting exposure. A particular emphasis is on reviewing the main EMF exposure assessment approaches found in the literature. Exposure assessment is carried out either by measuring the unperturbed magnetic fields in the MRI rooms, or by personal monitoring campaigns, or by the use of numerical methods. A general lack of standardization of the procedures and technologies adopted for exposure assessment has emerged, which makes it difficult to perform a direct comparison of results from different studies carried out by applying different assessment strategies. In conclusion, exposure assessment approaches based on data collection and numerical models need to be better defined in order to respond to specific research questions. That would provide for a more complete characterization of the exposure patterns and for identification of the factors determining the exposure variability. Graphical abstract Main approaches adopted in the literature to perform occupational exposure assessment to electromagnetic fields (EMFs) in magnetic resonance imaging (MRI) environments. SMF: static magnetic field; GMF: gradient magnetic fields; RF: radio-frequencies.

Exposure levels of radiofrequency magnetic fields and static magnetic fields in 1.5 and 3.0 T MRI units

“…The present guidelines focus on limiting occupational exposure to SMFs (ICNIRP [18]), high RF EMFs (ICNIRP [19]) and time-varying magnetic fields (ICNIRP [20]) that produces induced health outcomes as a result of movement of workers in the MRI (ICNIRP [20]; [21]. According to SCENIHR [22] and Frankel et al [3], little attention has been given to cases where there is exposure to different MRI-related EMFs at the same time.…”

Electromagnetic Exposure of Personnel Involved in Cardiac MRI Examinations in 1.5T, 3T and 7T Scanners

“…In line with common practice, the orthogonal components of the B-field (Bx, By, Bz) were recorded at the same time-points (t), and used to calculate the absolute values of B vector (i.e., SEmf) and dB/dt (i.e., TVEmf) [ 11 , 12 , 13 , 14 , 15 , 18 , 25 , 27 , 28 , 29 ]: …”

“…Alternatively, pharmaceuticals are administered by infusion pump during the acquisition procedure. Typically, it is not common for radiographers, nurses and clinicians (cardiologists, anaesthesiologists or radiologists) to stay with patients while scans are being taken, so they may generally be exposed to STmf only, i.e., they are not affected by the radiofrequencies and gradient fields used to scan patients [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ].…”

Influence of the static magnetic field on cell response in a miniaturized optically accessible bioreactor for 3D cell culture

“…For medical and research purposes, stronger SMFs may be applied. For instance, for magnetic resonance imaging (MRI) the magnetic field can reach intensities up to 3 T (Hartwig et al 2018 ), while the operators are exposed to a magnetic field varying from 0.5 to 2 mT (Zannella 1997 ).…”