Frank de Vocht1, Floris Muller, Hans Engels, Hans Kromhout. 1. Occupational and Environmental Health Research Group, School of Translational Medicine, Faculty of Medical and Human Sciences, University of Manchester, Manchester, United Kingdom. frank.devocht@manchester.ac.uk
Abstract
PURPOSE: To assess personal time-weighted average (TWA) static magnetic field and time-varying magnetic field 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.
PURPOSE: To assess personal time-weighted average (TWA) static magnetic field and time-varying magnetic field 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.
Authors: Frank de Vocht; Evridiki Batistatou; Anna Mölter; Hans Kromhout; Kristel Schaap; Martie van Tongeren; Stuart Crozier; Penny Gowland; Stephen Keevil Journal: Eur Radiol Date: 2015-03-13 Impact factor: 5.315
Authors: Giuseppe Acri; Patrizia Inferrera; Lucia Denaro; Carlo Sansotta; Elisa Ruello; Carmelo Anfuso; Francesca Maria Salmeri; Girolamo Garreffa; Giuseppe Vermiglio; Barbara Testagrossa Journal: Int J Environ Res Public Health Date: 2018-06-21 Impact factor: 3.390