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 language | English |
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Pages (from-to) | 1223-1228 |
Number of pages | 6 |
Journal | Journal of Magnetic Resonance Imaging |
Volume | 30 |
Issue number | 5 |
DOIs | |
Publication status | Published - Nov 2009 |
Keywords
- exposure assessment
- system tests
- exposure limits
- static fields
- time-varying fields
- OCCUPATIONAL-EXPOSURE
- SCANNERS
- GRADIENT
- LIMITS
- PERFORMANCE
- GUIDELINES
- WORKERS
- FUTURE