| Occupational exposure to static and time-varying gradient magnetic fields in MR units. | |
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MedLine Citation:
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PMID: 17969141 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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PURPOSE: To assess exposure of MR staff to static and time-varying gradient magnetic fields by direct measurement and questionnaire and to compare these to the action values and exposure limits stated in published guidance. MATERIALS AND METHODS: Instantaneous and time-averaged exposure to static magnetic fields were measured on clinical and research MR scanners. A questionnaire was sent to 100 clinical MR centers to estimate the average static field exposure. Instantaneous measurements of the time-varying magnetic field were conducted on a 1.5 T conventional and a 0.6 T open-bore MR system. RESULTS: The 24-hour time-averaged static field exposure was measured to be 1.8 +/- 1 mT and the questionnaire produced a 24-hour time-average of 2.3 mT. The maximum static field strength recorded during patient set up was 554 mT. Time-varying gradient field exposure was found to exceed the action values up to 30 cm from the bore entrance or magnet rim. CONCLUSION: The time-varying gradient field exposure limit is the only limit to be exceeded. The time-averaged static field exposure to staff was found to be 100 times lower than the recommended guidelines. |
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Authors:
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Jill K Bradley; Matilda Nyekiova; David L Price; Lindsay D'jon Lopez; Therese Crawley |
Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Journal of magnetic resonance imaging : JMRI Volume: 26 ISSN: 1053-1807 ISO Abbreviation: J Magn Reson Imaging Publication Date: 2007 Nov |
Date Detail:
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Created Date: 2007-11-05 Completed Date: 2008-01-22 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9105850 Medline TA: J Magn Reson Imaging Country: United States |
Other Details:
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Languages: eng Pagination: 1204-9 Citation Subset: IM |
Affiliation:
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Department of Medical Physics and Clinical Engineering, Oxford Radcliffe Hospitals Trust, Oxford, UK. jill.bradley@orh.nhs.uk |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Body Burden* Electromagnetic Fields* Great Britain Health Personnel / statistics & numerical data* Humans Magnetic Resonance Imaging / statistics & numerical data* Occupational Exposure / analysis*, statistics & numerical data* Radiation Dosage Radiation Monitoring / statistics & numerical data* Relative Biological Effectiveness Risk Assessment |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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