| Heating in the MRI environment due to superparamagnetic fluid suspensions in a rotating magnetic field. | |
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MedLine Citation:
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PMID: 20161608 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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In the presence of alternating-sinusoidal or rotating magnetic fields, magnetic nanoparticles will act to realign their magnetic moment with the applied magnetic field. The realignment is characterized by the nanoparticle's time constant, tau. As the magnetic field frequency is increased, the nanoparticle's magnetic moment lags the applied magnetic field at a constant angle for a given frequency, Omega, in rad/s. Associated with this misalignment is a power dissipation that increases the bulk magnetic fluid's temperature which has been utilized as a method of magnetic nanoparticle hyperthermia, particularly suited for cancer in low-perfusion tissue (e.g., breast) where temperature increases of between 4 degrees C and 7 degrees C above the ambient in vivo temperature cause tumor hyperthermia. This work examines the rise in the magnetic fluid's temperature in the MRI environment which is characterized by a large DC field, B(0). Theoretical analysis and simulation is used to predict the effect of both alternating-sinusoidal and rotating magnetic fields transverse to B(0). Results are presented for the expected temperature increase in small tumors (~1 cm radius) over an appropriate range of magnetic fluid concentrations (0.002 to 0.01 solid volume fraction) and nanoparticle radii (1 to 10 nm). The results indicate that significant heating can take place, even in low-field MRI systems where magnetic fluid saturation is not significant, with careful selection of the rotating or sinusoidal field parameters (field frequency and amplitude). The work indicates that it may be feasible to combine low-field MRI with a magnetic hyperthermia system using superparamagnetic iron oxide nanoparticles. |
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Authors:
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P Cantillon-Murphy; L L Wald; E Adalsteinsson; M Zahn |
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Publication Detail:
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Type: JOURNAL ARTICLE |
Journal Detail:
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Title: Journal of magnetism and magnetic materials Volume: 322 ISSN: 0304-8853 ISO Abbreviation: - Publication Date: 2010 Mar |
Date Detail:
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Created Date: 2010-7-13 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101314425 Medline TA: J Magn Magn Mater Country: - |
Other Details:
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Languages: ENG Pagination: 727-733 Citation Subset: - |
Affiliation:
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Department of Gastroenterology, Brigham and Women's Hospital, Boston, MA. |
Export Citation:
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Descriptor/Qualifier:
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| Grant Support | |
ID/Acronym/Agency:
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R01 EB007942-02//NIBIB NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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