Simultaneous imaging of magnetic nanoparticle concentration, temperature and viscosity with a scanning magnetic particle spectrometer

Abstract

A new approach of simultaneous imaging of magnetic nanoparticle (MNP) concentration, temperature and viscosity with a custom-built scanning magnetic particle spectrometer (SMPS) is presented. The fundamental f₀ and the 3f₀ and 5f₀ harmonics of the MNPs dominated by Brownian relaxation are measured with the SMPS. The effects of viscosity and temperature on the harmonics are studied in ac magnetic fields with different frequencies and amplitudes. Afterwards, phantom experiments are performed on the MNP samples with different spatial distributions of viscosity and temperature, which demonstrates the feasibility of the proposed approach for simultaneous imaging of MNP concentration, temperature and viscosity imaging.