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Ultra-Low Field MR Imaging

Working Group 8.24

Magnetic resonance imaging in extremely low magnetic fields


Magnetic resonance imaging (MRI) under extremely low magnetic fields opens up a new range of possibilities to gain insight into chemical and physical phenomena. The PTB supports the area of ultra-low field (ULF) MRI through the development and characterisation of equipment for ULF use, such as ultra-sensitive sensors and magnetic shielding. These developments make possible MRI at ULF, enabling and use of alternative contrast profiles to traditional MRI and the ability to optimise MRI signal enhancement methodologies from a new perspective. Additionally, we implement SQUID-based technology in the development of novel biomagnetic measurement techniques.


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Current projects of working group 8.24


  • DFG-Project „Stand alone two-phase parahydrogen induced hyperpolarizer for ultra-low and high field MR – 2P PHIP“ with Max-Planck-Institute Tübingen, OvG University Magdeburg and Christian-Albrechts-University Kiel

    The aim of this project is the development of a biocompatible setup for the characterisation of hyperpolarisation from Signal Amplification By Reversible Exchange (SABRE) for its eventual implementation in in vitro systems.

(Left) Bubbling of parahydrogen gas through a liquid sample lead to (right) orders of magnitude increase in signal via SABRE


  • DFG-Projekt „Multichannel single trial MEG of cortical population spikes – SPIKE MEG“ with Charité Berlin

    The aim of this project is the development of a state of the art, ultra-low noise multichannel MEG system for the non-invasive measurement of high frequency neuronal action potentials (SPIKES)

Time-resolved high frequency neuronal signals were measured with the high sensitivity single channel SQUID system at the PTB (adapted from Opens external link in new windowWaterstraat et al., PNAS, 118, e201740118 (2021),Opens external link in new window doi: 10.1073/pnas.2017401118).


  •  „Next generation of PTB-SQUID-Sensors“ with Departments 7.6 und 2.4
    The aim of this project is the development of new SQUID sensors that will have significantly improved signal-resolving capability for the measurement of neuromagnetic signals.


Basis of the Next Generation SQUID Sensor at PTB: sub-µm Josephson Contact. (adapted from Opens external link in new windowStorm et al. IEEE TAS, 30, 1-5 (2020), doi: 10.1109/TASC.2020.2989630)

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Together with other research groups we perform experiments on magnetic reonance imaging in extremely low environmental magnetic fields. After negotiation these measurements can also be performed by PTB on request.

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Selected publications of working group 8.24

Körber, R. et al., “SQUID current sensors with an integrated thermally actuated input current limiter,” Superconductor Science and Technology 36, 75007 (2023), doi: 10.1088/1361-6668/acd607.

G. Waterstraat, R. Körber, J.-H. Storm, and G. Curio, “Noninvasive neuromagnetic single-trial analysis of human neocortical population spikes,” Proceedings of the National Academy of Sciences, vol. 118, no. 11, p. e2017401118, 2021, doi: 10.1073/pnas.2017401118.

N. Höfner, J.-H. Storm, P. Hömmen, A. M. Cassarà, and R. Körber, “Computational and Phantom-Based Feasibility Study of 3D dcNCI With Ultra-Low-Field MRI,” Frontiers in Physics, vol. 9, p. 177, 2021, doi: 10.3389/fphy.2021.647376.

P. Hömmen et al., “Evaluating the Performance of Ultra-Low-Field MRI for in-vivo 3D Current Density Imaging of the Human Head,” Frontiers in Physics, vol. 8, p. 105, 2020, doi: 10.3389/fphy.2020.00105.

J.-H. Storm, O. Kieler, and R. Körber, “Towards Ultrasensitive SQUIDs Based on Submicrometer-Sized Josephson Junctions,” IEEE Transactions on Applied Superconductivity, vol. 30, no. 7, pp. 1–5, 2020, doi: 10.1109/tasc.2020.2989630.

J.-H. Storm, P. Hömmen, N. Höfner, and R. Körber, “Detection of body noise with an ultra-sensitive SQUID system,” Meas. Sci. Technol., vol. 30, no. 12, p. 125103, 2019, doi: 10.1088/1361-6501/ab3505.

P. Hömmen, J.-H. Storm, N. Höfner, and R. Körber, “Demonstration of full tensor current density imaging using ultra-low field MRI,” Magnetic Resonance Imaging, vol. 60, pp. 137–144, 2019, doi: 10.1016/j.mri.2019.03.010.

R. Körber, O. Kieler, P. Hömmen, N. Höfner, and J. Storm, “Ultra-sensitive SQUID systems for applications in biomagnetism and ultra-low field MRI,” in 2019 IEEE International Superconductive Electronics Conference (ISEC), 2019, pp. 1–3. doi: 10.1109/ISEC46533.2019.8990912.

E. Al-Dabbagh, J.-H. Storm, and R. Körber, “Ultra-sensitive SQUID Systems for Pulsed Fields—Degaussing Superconducting Pick-Up Coils,” IEEE Transactions on Applied Superconductivity, vol. 28, no. 4, pp. 1–5, 2018, doi: 10.1109/tasc.2018.2797544.

J.-H. Storm, P. Hömmen, D. Drung, and R. Körber, “An ultra-sensitive and wideband magnetometer based on a superconducting quantum interference device,” Appl. Phys. Lett., vol. 110, no. 7, p. 72603, 2017, doi: 10.1063/1.4976823.

R. Körber, “Ultra-sensitive SQUID instrumentation for MEG and NCI by ULF MRI,” in EMBEC & NBC 2017, Springer Singapore, 2017, pp. 795–798. doi: 10.1007/978-981-10-5122-7_199.

Storm, J.-H., Drung, D., Burghoff, M. & Körber, R. “A modular, extendible and field-tolerant multichannel vector magnetometer based on current sensor SQUIDs.” Superconductor Science and Technology 29, 94001 (2016).

Körber, R. et al. “SQUIDs in biomagnetism: a roadmap towards improved healthcare.” Superconductor Science and Technology 29, 113001 (2016).



Past projects of working group 8.24

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