| Occupational exposure measurements of static and pulsed gradient magnetic fields in the vicinity of MRI scanners. | |
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MedLine Citation:
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PMID: 19293469 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Recent advances in magnetic resonance imaging (MRI) have increased occupational exposure to magnetic fields. In this study, we examined the assessment of occupational exposure to gradient magnetic fields and time-varying magnetic fields generated by motion in non-homogeneous static magnetic fields of MRI scanners. These magnetic field components can be measured simultaneously with an induction coil setup that detects the time rate of change of magnetic flux density (dB/dt). The setup developed was used to measure the field components around two MRI units (1 T open and 3 T conventional). The measured values can be compared with dB/dt reference levels derived from magnetic flux density reference levels given by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The measured motion-induced dB/dt values were above the dB/dt reference levels for both MRI units. The measured values for the gradient fields (echo planar imaging (EPI) and fast field echo (FFE) sequences) also exceeded the dB/dt reference levels in positions where the medical staff may have access during interventional procedures. The highest motion-induced dB/dt values were 0.7 T s(-1) for the 1 T scanner and 3 T s(-1) for the 3 T scanner when only the static field was present. Even higher values (6.5 T s(-1)) were measured for simultaneous exposure to motion-induced and gradient fields in the vicinity of the 3 T scanner. |
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Authors:
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Sami Kännälä; Tim Toivo; Tommi Alanko; Kari Jokela |
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Publication Detail:
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Type: Journal Article Date: 2009-03-17 |
Journal Detail:
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Title: Physics in medicine and biology Volume: 54 ISSN: 0031-9155 ISO Abbreviation: Phys Med Biol Publication Date: 2009 Apr |
Date Detail:
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Created Date: 2009-03-18 Completed Date: 2009-06-12 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0401220 Medline TA: Phys Med Biol Country: England |
Other Details:
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Languages: eng Pagination: 2243-57 Citation Subset: IM |
Affiliation:
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STUK-Radiation and Nuclear Safety Authority, 00881 Helsinki, Finland. sami.kannala@stuk.fi |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Feasibility Studies Humans Magnetic Resonance Imaging / adverse effects*, instrumentation* Magnetics* Movement Occupational Exposure* Time Factors |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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