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

Giuseppe Acri, Patrizia Inferrera, Lucia Denaro, Carlo Sansotta, Elisa Ruello, Carmelo Anfuso, Francesca Maria Salmeri, Girolamo Garreffa, Giuseppe Vermiglio, Barbara Testagrossa

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Article number1298
JournalInternational Journal of Environmental Research and Public Health
Issue number7
Publication statusPublished - Jun 21 2018


  • Adult
  • Body Burden
  • Female
  • Guidelines as Topic
  • Humans
  • Magnetic Fields/adverse effects
  • Magnetic Resonance Imaging/adverse effects
  • Male
  • Maximum Allowable Concentration
  • Medical Staff
  • Middle Aged
  • Occupational Exposure/legislation & jurisprudence
  • Radiation Monitoring/methods


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