Quantitative 2D Magnetorelaxometry Imaging of Magnetic Nanoparticles Using Optically Pumped Magnetometers

For biomagnetical applications exploiting physical properties of magnetic nanoparticles (MNP), e.g., magnetic hyperthermia, knowledge about the quantitative spatial MNP distribution is crucial, which can be extracted by magnetorelaxometry (MRX) imaging. In this paper, we present quantification, quantitative 1D reconstruction, and quantitative 2D imaging of MNP by exploiting optically pumped magnetometers for MRX. While highlighting the potential of commercially available optically pumped magnetometers (OPM) for MRXI, we discuss current limitations of the used OPM. We show, that with our OPM setup, MNP can be precisely quantified with iron amounts down to ≈6 μg, which can be improved easily. With a 1D-reconstruction setup, point-like and complex MNP phantoms can be reconstructed quantitatively with high precision and accuracy. We show that with our developed 2D MRX imaging setup, which measures 12 cm by 8 cm, point-like MNP distributions with clinically relevant iron concentrations can be reconstructed precisely and accurately. Our 2D setup has the potential to be easily extended to a tomography styled (and thus slice-selective) 3D scanner, by adding a mechanical axis to the phantom.

[1]  Effective Viscosity of Magnetic Suspensions , 2011 .

[2]  Lutz Trahms,et al.  Cross-validation of microfabricated atomic magnetometers with superconducting quantum interference devices for biomagnetic applications , 2010 .

[3]  F Thiel,et al.  Demagnetization of magnetically shielded rooms. , 2007, The Review of scientific instruments.

[4]  Frank Ludwig,et al.  Magnetorelaxometry of magnetic nanoparticles with fluxgate magnetometers for the analysis of biological targets , 2005 .

[5]  G. Crevecoeur,et al.  Multi-color magnetic nanoparticle imaging using magnetorelaxometry , 2017, Physics in medicine and biology.

[6]  Lutz Trahms,et al.  Magnetorelaxometry procedures for quantitative imaging and characterization of magnetic nanoparticles in biomedical applications , 2015, Biomedizinische Technik. Biomedical engineering.

[7]  Luc Dupré,et al.  Model-based optimal design of a magnetic nanoparticle tomographic imaging setup , 2018, 2018 IEEE 15th International Symposium on Biomedical Imaging (ISBI 2018).

[8]  Robert H. Halstead,et al.  Matrix Computations , 2011, Encyclopedia of Parallel Computing.

[9]  Richard H. Byrd,et al.  Approximate solution of the trust region problem by minimization over two-dimensional subspaces , 1988, Math. Program..

[10]  L. Trahms,et al.  Aggregation behaviour of magnetic nanoparticle suspensions investigated by magnetorelaxometry , 2006 .

[11]  Simone Colombo,et al.  A magnetic source imaging camera , 2016 .

[12]  Lea Fleischer,et al.  Regularization of Inverse Problems , 1996 .

[13]  U. Steinhoff,et al.  Interpreting the magnetorelaxometry signal of suspended magnetic nanoparticles with Kaczmarz’ algorithm , 2017 .

[14]  B. Tanner,et al.  Time-dependent magnetization in fine-particle ferromagnetic systems , 1983 .

[15]  Maik Liebl,et al.  Quantitative Bildgebung magnetischer Nanopartikel mittels magnetrelaxometrischer Tomographie für biomedizinische Anwendungen , 2017 .

[16]  J. W. Brown.  Thermal Fluctuations of a Single-Domain Particle , 1963 .

[17]  F. Ludwig,et al.  Quantitative and Qualitative Characterization of Magnetic Nanoparticles by Magnetorelaxometry using a Laboratory MRX Analyzer , 2009 .

[18]  T. W. Kornack,et al.  A subfemtotesla multichannel atomic magnetometer , 2003, Nature.

[19]  Magnetic source imaging , 2018, Zeitschrift für Epileptologie.

[20]  J. Osborne,et al.  Fully integrated standalone zero field optically pumped magnetometer for biomagnetism , 2018, OPTO.

[21]  A. Petri‐Fink,et al.  A quantitative study of particle size effects in the magnetorelaxometry of magnetic nanoparticles using atomic magnetometry , 2015 .

[22]  L Trahms,et al.  Quantification of magnetic nanoparticles by magnetorelaxometry and comparison to histology after magnetic drug targeting. , 2006, Journal of nanoscience and nanotechnology.

[23]  Daniel Baumgarten,et al.  Optimizing Excitation Coil Currents for Advanced Magnetorelaxometry Imaging , 2019, Journal of Mathematical Imaging and Vision.

[24]  L. Trahms,et al.  Magnetorelaxometry for In-Vivo Quantification of Magnetic Nanoparticle Distributions after Magnetic Drug Targeting in a Rabbit Carcinoma Model , 2012 .

[25]  S. Haroche,et al.  Detection of very weak magnetic fields (10−9gauss) by 87Rb zero-field level crossing resonances , 1969 .

[26]  Lutz Trahms,et al.  Magnetorelaxometry Assisting Biomedical Applications of Magnetic Nanoparticles , 2011, Pharmaceutical Research.

[27]  J Haueisen,et al.  Quantitative imaging of magnetic nanoparticles by magnetorelaxometry with multiple excitation coils , 2014, Physics in medicine and biology.

[28]  G. Crevecoeur,et al.  Regarding the Néel relaxation time constant in magnetorelaxometry , 2014 .

[29]  Oswaldo Baffa,et al.  Development of an optical pumped gradiometric system to detect magnetic relaxation of magnetic nanoparticles , 2019, Journal of Magnetism and Magnetic Materials.

[30]  Luc Dupre,et al.  Advancements in Magnetic Nanoparticle Reconstruction Using Sequential Activation of Excitation Coil Arrays Using Magnetorelaxometry , 2012, IEEE Transactions on Magnetics.

[31]  Lutz Trahms,et al.  How the size distribution of magnetic nanoparticles determines their magnetic particle imaging performance , 2011 .

[32]  Eko Supriyanto,et al.  Plane-wise sensitivity based inhomogeneous excitation fields for magnetorelaxometry imaging of magnetic nanoparticles , 2015 .

[33]  Q. Pankhurst,et al.  Applications of magnetic nanoparticles in biomedicine , 2003 .