Dr. Kai Buckenmaier

Address: Spemannstr. 41
72076 Tübingen
Room number: 3.B.03
Phone: +49 7071 601 928
Fax: +49 7071 601 702
E-Mail: Kai.Buckenmaier


Picture of Buckenmaier, Kai, Dr.

Kai Buckenmaier

Position: Projektleiter  Unit: Scheffler

Ultra lowfield magnetic resonance imaging for the development of in vivo hyperpolarization techniques

Hyperpolarization techniques for MRI and NMR, such as ODNP (Overhauser Dynamic Nuclear Polarization) or parahydrogen based hyperpolarization, are working best at field strengths in the mT range. To investigate these techniques a NMR/MRI system operating at static magnetic fields ranging from the earth field up to a few mT was developed and built.

In order to detect a NMR signal at those low fields corresponding to Larmor frequencies in the kHz range, conventional Faraday coils are not optimal any more, since their sensitivity decreases for decreasing frequencies. Using a SQUID (Superconducting QUantum Intereference Device) based detector circumvents that issue. This detector is a broadband detector, which measures the magnetic flux directly rather than the change of the magnetic flux, making the amplitude of the NMR signal independent of the frequency. These kind of sensors are also used for the detection of MEG (MagnetoEncephaloGraphy) signals.

The boost in signal due to the hyperpolarization of the sample can be used to realize functional MRI at ultralow fields. This would be an important step in the direction of combining functional MRI at ultralow fields with MEG. The advantage of such a system would be the high temporal resolution of MEG combined with the high spatial resolution of fMRI.

The aims of the project are:

  • Development and construction of a low noise NMR/MRI setup using a SQUID sensor
  • Optimizing hyperpolarized contrast agents to make them suitable for first in vivo tests
  • Development of in vivo hyperpolarization techniques based on ODNP

Safety simulations of RF coils for magnetic resonance imaging at 9.4 T

High static magnetic fields in magnetic resonance imaging have the advantage, that images with very high spatial and temporal resolution can be acquired. However the short wavelength of the required RF coils lead to interference effects. Inhomogeneous excitation fields that might lead to local heating are a result of this effect.

In order to guarantee safety for human subjects the performance of the home made RF coils need to be simulated to assure that the specific absorption rate limit is not exceeded.

Current Position:

Project leader at the Max-Planck-Institute for Biological Cybernetics



Study of physics at the university of Tübingen, Germany.

Diploma thesis on 'spectroscopy of fractional Josephson vortices'


PhD thesis at the University of Tübingen on 'activation energy of fractional vortices and spectroscopy of vortex molecules in long Josephson Junctions'.


Research scientist at the physics department of the University of Tübingen, Germany.


Research scientist at the physics department of the University of Berkeley, USA.

since 2013

Project leader at the Max-Planck Institute for Biological Cybernetics, Tübingen, Germany

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Articles (7):

Mirkes C, Shajan G, Chadzynski G, Buckenmaier K, Bender B and Scheffler K (June-2016) 31P CSI of the human brain in healthy subjects and tumor patients at 9.4 T with a three-layered multi-nuclear coil: initial results Magnetic Resonance Materials in Physics, Biology and Medicine 29(3) 579-589.
Mirkes C, Shajan G, Bause J, Buckenmaier K, Hoffmann J and Scheffler K (March-2016) Triple-quantum-filtered sodium imaging at 9.4 Tesla Magnetic Resonance in Medicine 75(3) 1278–1289.
Shajan G, Mirkes C, Buckenmaier K, Hoffmann J, Pohmann R and Scheffler K (February-2016) Three-layered radio frequency coil arrangement for sodium MRI of the human brain at 9.4 Tesla Magnetic Resonance in Medicine 75(2) 906–916.
Zbýn Š, Brix MO, Juras V, Domayer SE, Walzer SM, Mlynarik V, Apprich S, Buckenmaier K, Windhager R and Trattnig S (April-2015) Sodium Magnetic Resonance Imaging of Ankle Joint in Cadaver Specimens, Volunteers, and Patients After Different Cartilage Repair Techniques at 7 T: Initial Results Investigative Radiology 50(4) 246–254.
Boss MA, Mates JAB, Busch SE, SanGiorgio P, Russek SE, Buckenmaier K, Irwin KD, Cho H-M, Hilton GC and Clarke J (December-2014) Prototype phantoms for characterization of ultralow field magnetic resonance imaging Magnetic Resonance in Medicine 72(6) 1793–1800.
Inglis B, Buckenmaier K, SanGiorgio P, Pedersen AF, Nichols MA and Clarke J (November-2013) MRI of the human brain at 130 microtesla Proceedings of the National Academy of Sciences of the United States of America 110(48) 19194–19201.
Kienzle U, Meckbach JM, Buckenmaier K, Gaber T, Sickinger H, Kaiser C, Ilin K, Siegel M, Koelle D, Kleiner R and Goldobin E (January-2012) Spectroscopy of a fractional Josephson vortex molecule Physical Review B 85(1) 1-8.

Conference papers (1):

Mirkes C, Shajan G, Hoffmann J, Bause J, Buckenmaier K and Scheffler K (November-2015) Natrium MRT bei 9,4 Tesla, 18. Jahrestagung der Deutschen Sektion der ISMRM e.V. (DS ISMRM 2015), 23-27.

Posters (2):

Buckenmaier K, Rudolph M, Tomasz M, Rudin J, Mayer H, Koelle D, Kleiner R and Scheffler K (March-9-2016): SQUID based magnetic resonance imaging for the investigation of hyperpolarized samples, 11th Annual Meeting of the European Society for Molecular Imaging (EMIM 2016), Utrecht, The Netherlands.
Mirkes C, Shajan G, Bause J, Buckenmaier K, Hoffmann J and Scheffler K (June-4-2015): Triple-quantum-filtered sodium imaging at 9.4 Tesla, 23rd Annual Meeting and Exhibition of the International Society for Magnetic Resonance in Medicine (ISMRM 2015), Toronto, Canada.

Theses (1):

Buckenmaier K: Aktivierungsenergie fraktionaler Flusswirbel und Spektroskopie an Vortex-Molekülen in langen Josephsonkontakten [Activation energy of fractional vortices and spectroscopy of a vortex molecule in long Josephson junction], Eberhard-Karls-Universität Tübingen, (June-2010). PhD thesis

Popular Scientific Articles (1):

Buckenmaier K, Shajan G, Chadzynski G, Hoffmann J, Pohmann R and Scheffler K: Magnetresonanztomografie bei ultrahohen Feldstärken - Forschungsbericht 2014 Max-Planck-Institut für biologische Kybernetik, Jahrbuch der Max-Planck-Gesellschaft 2014.

Talks (2):

Rudolph M, Misztal T, Antkowiak P, Meyer H, Kleiner R, Koelle D, Scheffler K and Buckenmaier K (March-9-2016) Abstract Talk: Ultra low field magnetic resonance imaging for the investigation of hyperpolarized contrast agents, 80. Jahrestagung der DPG und DPG-Frühjahrstagung, Regensburg, Germany(TT 51.4).
Buckenmaier K (May-7-2015) Invited Lecture: Safety Evaluation and Operational Procedures for Self-Developed RF coils & Simulation of 9.4 T 1H/X-Nuclei RF coil combinations, 5th BioEM Simulation Meeting, Magdeburg, Germany.

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Last updated: Tuesday, 18.11.2014