Personal Exposure to Static and Time-Varying Magnetic Fields During MRI System Test Procedures

Frank de Vocht*, Floris Muller, Hans Engels, Hans Kromhout

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

32 Citations (Scopus)

Abstract

Purpose: To assess personal time-weighted average (TWA) static magnetic field and time-varying magnetic filed exposure for several system testing tasks routinely conducted by engineers at an MRI manufacturing plant.

Materials and Methods: Personal exposure was measured using a personal dosimeter that measured B and dB/dt in all three orthogonal directions with a 1 Hz frequency. TWA exposure was calculated and random effects and linear mixed effects models were used to assess exposure levels and variability.

Results: Whereas full-body peak (2T) and TWA (200 mT/8 h) exposure limits for the static magnetic field originally, proposed by ICNIRP were not exceeded time-varying magnetic field peaks (dB/dt) did exceed the proposed threshold value (767.9 mT/s) suggested by IEEE on several occasions at the 3.0 Tesla (T) whole-body cylindrical system.

Conclusion: TWA exposure levels are well below the proposed limit values, but peak exposure limits are exceeded during certain procedures performed on 1.0T to 3.0T systems.

Original languageEnglish
Pages (from-to)1223-1228
Number of pages6
JournalJournal of Magnetic Resonance Imaging
Volume30
Issue number5
DOIs
Publication statusPublished - Nov 2009

Keywords

  • exposure assessment
  • system tests
  • exposure limits
  • static fields
  • time-varying fields
  • OCCUPATIONAL-EXPOSURE
  • SCANNERS
  • GRADIENT
  • LIMITS
  • PERFORMANCE
  • GUIDELINES
  • WORKERS
  • FUTURE

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