title: Work-related factors associated with occupational exposure to static magnetic stray fields from MRI scanners.
abstract: OBJECTIVE
  This study aims to identify work-related and personal factors associated with workers' exposure to static magnetic fields (SMF) and motion-induced time-varying magnetic fields (TVMF) from MRI scanners.
  
  
  METHODS
  Measurements of personal exposure to SMF and TVMF were performed among MRI staff during 439 work shifts at 14 different workplaces using portable magnetic field dosimeters. These data were coupled with contextual workplace and worker information. After data cleanup, 324 remaining observations were used to develop linear mixed effects models for various measures of peak and time-weighted average (TWA) exposure.
  
  
  RESULTS
  Exposure levels near whole-body closed-bore scanners increased by 30% to 76% for each additional tesla of scanner strength, depending on exposure metric. Small-bore animal scanners, on the other hand, showed a reversed association with scanner strength. Measures of peak and TWA exposure were differently associated with specific tasks and scan procedures. In addition, body height of the worker was negatively associated with measured exposure levels.
  
  
  CONCLUSIONS
  The study revealed workplace characteristics, scan activities, and personal characteristics associated with SMF and TVMF exposure levels of MRI staff and was able to quantify the unique contribution of each of these factors while adjusting for the presence of others.
authors.affiliation: Institute for Risk Assessment Sciences, Division of Environmental Epidemiology, Utrecht University, Utrecht, the Netherlands.
authors.forename: Kristel
authors.initials: K
authors.lastname: Schaap
authors.affiliation: Institute for Risk Assessment Sciences, Division of Environmental Epidemiology, Utrecht University, Utrecht, the Netherlands.
authors.forename: Yvette
authors.initials: Y
authors.lastname: Christopher-De Vries
authors.affiliation: Département des sciences de la santé communautaire, Université de Sherbrooke, Sherbrooke, Canada.
authors.forename: Évelyne
authors.initials: É
authors.lastname: Cambron-Goulet
authors.affiliation: Institute for Risk Assessment Sciences, Division of Environmental Epidemiology, Utrecht University, Utrecht, the Netherlands.
authors.forename: Hans
authors.initials: H
authors.lastname: Kromhout
mesh_terms: D000328:Adult; D000818:Animals; D001831:Body Temperature; D004574:Electromagnetic Fields; D004867:Equipment Design; D005260:Female; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009038:Motion; D016273:Occupational Exposure; D011874:Radiometry; D012044:Regression Analysis; D013997:Time Factors; D055815:Young Adult
keywords: MRI staff; exposure determinants; occupational exposure; static magnetic fields; time-varying magnetic fields