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Nano-Sized Ferrite Particles for Magnetic Resonance Imaging Thermometry



Janusz H. Hankiewicz, J A. Stoll, John Stroud, J Davidson, K L. Livesey, K Tvrdy, Alexana Roshko, Stephen E. Russek, Karl Stupic, P Bilski, Robert E. Camley


Recently, we reported the use of magnetic particles as temperature indicators in magnetic resonance imaging thermometry (tMRI). In this method, the brightness of the MR image changes with temperature due to a temperature-dependent magnetic field inhomogeneity caused by the dipolar field of the magnetic particles. Ferrites are a promising class of materials for tMRI applications because of their biocompatibility and because their magnetic properties can be varied by changing composition. Earlier studies used micrometer sized ferrite particles in a proof-of-concept demonstration. However, such large particles cannot be administered intravenously for in-vivo use. In this report, we demonstrate the use of nanoscale Co0.3Zn0.7Fe2O4 ferrite particles as temperature sensors for tMRI. Scanning transmission electron microscopy and X-ray diffraction showed that particles are crystalline and within a size range of 10-30 nm. Measurements of the temperature-dependent magnetization demonstrated a Curie temperature around 275 K. We conducted nuclear magnetic resonance (NMR) and MRI studies of samples with different concentrations of ferrite nanoparticles suspended in agar gel. The relative MR image intensity shows a near-linear temperature dependence. These ferrite nanoparticles, at low concentration (0.12 g/L), provide image contrast corresponding to a temperature resolution of ±1.5 K at 310 K, bolstering the potential viability of this material for clinical applications.
APL Materials


Thermometry, MRI, nanoparticles, ferrite


Hankiewicz, J. , Stoll, J. , Stroud, J. , Davidson, J. , Livesey, K. , Tvrdy, K. , Roshko, A. , Russek, S. , Stupic, K. , Bilski, P. and Camley, R. (2018), Nano-Sized Ferrite Particles for Magnetic Resonance Imaging Thermometry, APL Materials, [online], (Accessed June 23, 2024)


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Created September 7, 2018, Updated October 12, 2021