Université de Fribourg

Imaging magnetic nanoparticle distributions by atomic magnetometry-based susceptometry

Colombo, Simone ; Lebedev, Victor ; Tonyushkin, Alexey ; Pengue, Simone ; Weis, Antoine

In: IEEE Transactions on Medical Imaging, 2020, vol. 39, no. 4, p. 922–933

We introduce a Magnetic Particle Imaging Susceptometer (MPIS) that uses a high- sensitivity atomic magnetometer (AM) for recording the spatial distribution of fluid- suspended magnetic nanoparticles. We have evaluated the MPIS performance by one-dimensional scans of structured nanoparticle phantoms, demonstrating, in particular, resolutions of ≈2.5 mm prior to deconvolution and ≪1 mm after ...

Université de Fribourg

Orientational dependence of optically detected magnetic resonance signals in laser-driven atomic magnetometers

Colombo, Simone ; Dolgovskiy, Vladimir ; Scholtes, Theo ; Grujić, Zoran D. ; Lebedev, Victor ; Weis, Antoine

In: Applied Physics B, 2017, vol. 123, no. 1, p. 35

We have investigated the dependence of lock-in-demodulated Mx-magnetometer signals on the orientation of the static magnetic field B0 of interest. Magnetic resonance spectra for 2400 discrete orientations of B0 covering a 4π solid angle have been recorded by a PC-controlled steering and data acquisition system. Off-line fits by previously derived lineshape functions allow us to extract the...

Université de Fribourg

A magnetic source imaging camera

Dolgovskiy, Vladimir ; Fescenko, Ilja ; Sekiguchi, N. ; Colombo, Simone ; Lebedev, Victor ; Zhang, J. ; Weis, Antoine

In: Applied Physics Letters, 2016, vol. 109, no. 2, p. 023505

We describe a magnetic source imaging camera (MSIC) allowing a direct dynamic visualization of the two-dimensional spatial distribution of the individual components Bx(x,y), By(x,y) and Bz(x,y) of a magnetic field. The field patterns allow—in principle— a reconstruction of the distribution of sources that produce the field B→ by inverse problem analysis. We compare experimentally...

Université de Fribourg

M(H) dependence and size distribution of SPIONs measured by atomic magnetometry

Colombo, Simone ; Lebedev, Victor ; Grujic, Zoran Dragan ; Dolgovskiy, Vladimir ; Weis, Antoine

In: International Journal on Magnetic Particle Imaging, 2016, vol. 2, no. 1, p. -

We demonstrate that the quasistatic recording of the magnetic excitation function M(H) of superparamagnetic iron oxide magnetic nanoparticle (SPION) suspensions by an atomic magnetometer allows a precision determination of the sample’s iron mass contentmFe and the particle size distribution.

Université de Fribourg

MPS and ACS with an atomic magnetometer

Colombo, Simone ; Lebedev, Victor ; Grujic, Zoran Dragan ; Dolgovskiy, Vladimir ; Weis, Antoine

In: International Journal on Magnetic Particle Imaging, 2016, vol. 2, no. 1, p. -

We show that a single atomic magnetometer in a magnetically unshielded environment can be used to perform magnetic particle spectroscopy (MPS) and AC susceptometry (ACS) on liquid-suspended magnetic nanoparticles. We demonstrate methods allowing a simultaneous recording of M(H) and dM/dH(H) dependences of samples containing down to 1 μg of iron. Our results pave the way towards an atomic...

Université de Fribourg

A quantitative study of particle size effects in the magnetorelaxometry of magnetic nanoparticles using atomic magnetometry

Dolgovskiy, Vladimir ; Lebedev, Victor ; Colombo, Simone ; Weis, Antoine ; Michen, Benjamin ; Ackermann-Hirschi, Liliane ; Petri-Fink, Alke

In: Journal of Magnetism and Magnetic Materials, 2015, vol. 379, p. 137–150

The discrimination of immobilised superparamagnetic iron oxide nanoparticles (SPIONs) against SPIONs in fluid environments via their magnetic relaxation behaviour is a powerful tool for bio-medical imaging. Here we demonstrate that a gradiometer of laser-pumped atomic magnetometers can be used to record accurate time series of the relaxing magnetic field produced by pre-polarised SPIONs. We have...

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5 Colombo, Sara