Document Detail


Measurements of occupational exposure to switched gradient and spatially-varying magnetic fields in areas adjacent to 1.5 T clinical MRI systems.
MedLine Citation:
PMID:  17969176     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: To determine if magnetic field exposure close to two clinical 1.5 T magnetic resonance imaging (MRI) scanners during image acquisition and when moving in the spatially-varying static magnetic field is compliant with European Union (EU) Directive 2004/40/EC (the Directive). MATERIALS AND METHODS: Using commercially available equipment we measured the magnetic flux density around the scanners during two clinical pulse sequences. The data was compared with frequency-dependent limits that will limit occupational exposure following transposition of the Directive into national law in 2008. The static magnetic field was measured around the scanners and the exposure from movement within this field was simulated. RESULTS: The whole-body exposure experienced when standing close to the face of the magnet exceeds the limits in the Directive on the two scanners tested during clinical sequences. Simulation of movement toward the scanner shows that speeds must be restricted to 1/5 of normal walking speed to comply with the Directive. CONCLUSION: EU Directive 2004/40/EC will have a major impact on the current use and future development of MRI due to limitations on exposure to time-varying gradient fields and movement within the spatially-varying static field. This will make interventional work impossible and routine MRI use impracticable in Europe.
Authors:
Sophie F Riches; David J Collins; Geoffrey D Charles-Edwards; Jonathan C Shafford; Jonathan Cole; Stephen F Keevil; Martin O Leach
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of magnetic resonance imaging : JMRI     Volume:  26     ISSN:  1053-1807     ISO Abbreviation:  J Magn Reson Imaging     Publication Date:  2007 Nov 
Date Detail:
Created Date:  2007-11-05     Completed Date:  2008-01-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9105850     Medline TA:  J Magn Reson Imaging     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1346-52     Citation Subset:  IM    
Affiliation:
Cancer Research UK Clinical Magnetic Resonance Research Group, Royal Marsden NHS Trust and Institute of Cancer Research, Surrey, UK. sophie.riches@icr.ac.uk
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MeSH Terms
Descriptor/Qualifier:
Body Burden
Computer Simulation
Electromagnetic Fields
Great Britain
Humans
Magnetic Resonance Imaging / methods*
Magnetics / instrumentation*
Medical Staff
Models, Biological*
Occupational Exposure / analysis*
Radiation Dosage
Radiation Monitoring / methods
Relative Biological Effectiveness
Whole-Body Counting / methods*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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