| Numerical study of RF exposure and the resulting temperature rise in the foetus during a magnetic resonance procedure. | |
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MedLine Citation:
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PMID: 20090188 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Numerical simulations of specific absorption rate (SAR) and temperature changes in a 26-week pregnant woman model within typical birdcage body coils as used in 1.5 T and 3 T MRI scanners are described. Spatial distributions of SAR and the resulting spatial and temporal changes in temperature are determined using a finite difference time domain method and a finite difference bio-heat transfer solver that accounts for discrete vessels. Heat transfer from foetus to placenta via the umbilical vein and arteries as well as that across the foetal skin/amniotic fluid/uterine wall boundaries is modelled. Results suggest that for procedures compliant with IEC normal mode conditions (maternal whole-body averaged SAR(MWB) < or = 2 W kg(-1) (continuous or time-averaged over 6 min)), whole foetal SAR, local foetal SAR(10 g) and average foetal temperature are within international safety limits. For continuous RF exposure at SAR(MWB) = 2 W kg(-1) over periods of 7.5 min or longer, a maximum local foetal temperature >38 degrees C may occur. However, assessment of the risk posed by such maximum temperatures predicted in a static model is difficult because of frequent foetal movement. Results also confirm that when SAR(MWB) = 2 W kg(-1), some local SAR(10g) values in the mother's trunk and extremities exceed recommended limits. |
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Authors:
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J W Hand; Y Li; J V Hajnal |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-01-20 |
Journal Detail:
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Title: Physics in medicine and biology Volume: 55 ISSN: 1361-6560 ISO Abbreviation: Phys Med Biol Publication Date: 2010 Feb |
Date Detail:
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Created Date: 2010-02-03 Completed Date: 2010-04-23 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: 913-30 Citation Subset: IM |
Affiliation:
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Imaging Sciences Department, Imperial College London, London W12 0NN, UK. j.hand@imperial.ac.uk |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Computer Simulation* Female Fetus / physiology, radiation effects* Humans Magnetic Resonance Imaging* Models, Biological* Mothers Movement Pregnancy Radiation Radio Waves* Temperature* Time Factors |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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