Effect of Changing Iron Content and Excitation Frequency on Magnetic Particle Imaging Signal: A Comparative Study of Synomag® Nanoparticles

Authors: Kalthoum Riahi, Max T. Rietberg, Javier Perez y Perez, Corné Dijkstra, Bennie ten Haken, Lejla Alic

Abstract:

Magnetic nanoparticles (MNPs) are widely used to facilitate magnetic particle imaging (MPI) which has the potential to become the leading diagnostic instrument for biomedical imaging. This comparative study assesses the effects of changing iron content and excitation frequency on point-spread function (PSF) representing the effect of magnetization reversal. PSF is quantified by features of interest for MPI: i.e., drive field amplitude and full-width-at-half-maximum (FWHM). A superparamagnetic quantifier (SPaQ) is used to assess differential magnetic susceptibility of two commercially available MNPs: Synomag®-D50 and Synomag®-D70. For both MNPs, the signal output depends on increase in drive field frequency and amount of iron-oxide, which might be hampering the sensitivity of MPI systems that perform on higher frequencies. Nevertheless, there is a clear potential of Synomag®-D for a stable MPI resolution, especially in case of 70 nm version, that is independent of either drive field frequency or amount of iron-oxide.

Keywords: Magnetic nanoparticles, MNPs, Differential magnetic susceptibility, DMS, Magnetic particle imaging, MPI, magnetic relaxation, Synomag®-D.

References:

[1] E. Teeman, C. Shasha, J. E. Evans, and K. M. Krishnan, “Intracellular dynamics of superparamagnetic iron oxide nanoparticles for magnetic particle imaging,” Nanoscale, 2019.
[2] S. A. Shah, D. B. Reeves, R. M. Ferguson, J. B. Weaver, and K. M. Krishnan, “Mixed Brownian alignment and Néel rotations in superparamagnetic iron oxide nanoparticle suspensions driven by an ac field,” Phys. Rev. B - Condens. Matter Mater. Phys., 2015.
[3] F. Ludwig et al., “Characterization of magnetic nanoparticle systems with respect to their magnetic particle imaging performance,” Biomedizinische Technik. 2013.
[4] Z. W. Tay, D. W. Hensley, E. C. Vreeland, B. Zheng, and S. M. Conolly, “The relaxation wall: experimental limits to improving MPI spatial resolution by increasing nanoparticle core size,” Biomed. Phys. Eng. Express, 2017.
[5] P. J. Sehl, O.C.; Gevaert, J.J.; Melo, K.P.; Knier, N.N.; Foster, “A Perspective on Cell Tracking with Magnetic Particle Imaging.”
[6] L. Lartigue et al., “Cooperative organization in iron oxide multi-core nanoparticles potentiates their efficiency as heating mediators and MRI contrast agents,” ACS Nano, 2012.
[7] K. Riahi, M. M. van de Loosdrecht, L. Alic, and B. ten Haken, “Assessment of differential magnetic susceptibility in nanoparticles: Effects of changes in viscosity and immobilisation,” J. Magn. Magn. Mater., 2020.
[8] M. M. Van De Loosdrecht et al., “A novel characterization technique for superparamagnetic iron oxide nanoparticles: The superparamagnetic quantifier, compared with magnetic particle spectroscopy,” Rev. Sci. Instrum., vol. 90, no. 2, Feb. 2019.
[9] K. Riahi, M. M. van de Loosdrecht, L. Alic, and B. Ten Haken, “Magnetic performance of synomag nanoparticles in various environments,” Int. J. Magn. Part. Imaging, 2020.