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Magnetic nanoparticle temperature estimation
Author(s) -
Weaver John B.,
Rauwerdink Adam M.,
Hansen Eric W.
Publication year - 2009
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3106342
Subject(s) - materials science , temperature measurement , calibration , nanoparticle , magnetic nanoparticles , magnetization , magnetic field , amplitude , harmonics , field (mathematics) , nuclear magnetic resonance , biomedical engineering , biological system , nanotechnology , optics , physics , thermodynamics , voltage , medicine , statistics , mathematics , quantum mechanics , biology , pure mathematics
The authors present a method of measuring the temperature of magnetic nanoparticles that can be adapted to provide in vivo temperature maps. Many of the minimally invasive therapies that promise to reduce health care costs and improve patient outcomes heat tissue to very specific temperatures to be effective. Measurements are required because physiological cooling, primarily blood flow, makes the temperature difficult to predict a priori . The ratio of the fifth and third harmonics of the magnetization generated by magnetic nanoparticles in a sinusoidal field is used to generate a calibration curve and to subsequently estimate the temperature. The calibration curve is obtained by varying the amplitude of the sinusoidal field. The temperature can then be estimated from any subsequent measurement of the ratio. The accuracy was 0.3 °K between 20 and 50 ° C using the current apparatus and half‐second measurements. The method is independent of nanoparticle concentration and nanoparticle size distribution.