Florian Thieben, M.Sc.

Universitätsklinikum Hamburg-Eppendorf (UKE)
Sektion für Biomedizinische Bildgebung
Lottestraße 55
2ter Stock, Raum 202
22529 Hamburg
- Postanschrift -

Technische Universität Hamburg (TUHH)
Institut für Biomedizinische Bildgebung
Gebäude E, Raum 4.044
Am Schwarzenberg-Campus 3
21073 Hamburg

Tel.: 040 / 7410 56355
E-Mail: f.thieben(at)uke.de
E-Mail: florian.thieben(at)tuhh.de
ORCID: https://orcid.org/0000-0002-2890-5288

Research Interests

  • Magnetic Particle Imaging
  • Low noise electronics
  • Inductive sensors and filters
  • Magnetic Particle Imaging scanner characterization

Curriculum Vitae

Florian Thieben works as an electrical engineer in the group of Tobias Knopp for experimental Biomedical Imaging at the University Medical Center Hamburg-Eppendorf and the Hamburg University of Technology. In 2017 he graduated with a master's degree thesis on Entwicklung eines kompakten Magnet Partikel Spektrometers mit gradiometrischer Empfangskette".

Journal Publications

[178619]
Title: System Matrix Based Reconstruction for Pulsed Sequences in Magnetic Particle Imaging.
Written by: F. Mohn, T. Knopp, M. Boberg, F. Thieben, P. Szwargulski, and M. Graeser
in: <em>IEEE Transactions on Medical Imaging</em>. July (2022).
Volume: <strong>41</strong>. Number: (7),
on pages: 1862-1873
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DOI: 10.1109/TMI.2022.3149583
URL: https://ieeexplore.ieee.org/document/9706173
ARXIVID:
PMID:

[www]

Note: article, instrumentation

Abstract: Improving resolution and sensitivity will widen possible medical applications of magnetic particle imaging. Pulsed excitation promises such benefits, at the cost of more complex hardware solutions and restrictions on drive field amplitude and frequency. State-of-the-art systems utilize a sinusoidal excitation to drive superparamagnetic nanoparticles into the non-linear part of their magnetization curve, which creates a spectrum with a clear separation of direct feed-through and higher harmonics caused by the particles response. One challenge for rectangular excitation is the discrimination of particle and excitation signals, both broad-band. Another is the drive-field sequence itself, as particles that are not placed at the same spatial position, may react simultaneously and are not separable by their signal phase or shape. To overcome this potential loss of information in spatial encoding for high amplitudes, a superposition of shifting fields and drive-field rotations is proposed in this work. Upon close view, a system matrix approach is capable to maintain resolution, independent of the sequence, if the response to pulsed sequences still encodes information within the phase. Data from an Arbitrary Waveform Magnetic Particle Spectrometer with offsets in two spatial dimensions is measured and calibrated to guarantee device independence. Multiple sequence types and waveforms are compared, based on frequency space image reconstruction from emulated signals, that are derived from measured particle responses. A resolution of 1.0 mT (0.8 mm for a gradient of (−1.25,−1.25,2.5) T/m ) in x- and y-direction was achieved and a superior sensitivity for pulsed sequences was detected on the basis of reference phantoms.

Conference Proceedings

[178619]
Title: System Matrix Based Reconstruction for Pulsed Sequences in Magnetic Particle Imaging.
Written by: F. Mohn, T. Knopp, M. Boberg, F. Thieben, P. Szwargulski, and M. Graeser
in: <em>IEEE Transactions on Medical Imaging</em>. July (2022).
Volume: <strong>41</strong>. Number: (7),
on pages: 1862-1873
Chapter:
Editor:
Publisher:
Series:
Address:
Edition:
ISBN:
how published:
Organization:
School:
Institution:
Type:
DOI: 10.1109/TMI.2022.3149583
URL: https://ieeexplore.ieee.org/document/9706173
ARXIVID:
PMID:

[www] [BibTex]

Note: article, instrumentation

Abstract: Improving resolution and sensitivity will widen possible medical applications of magnetic particle imaging. Pulsed excitation promises such benefits, at the cost of more complex hardware solutions and restrictions on drive field amplitude and frequency. State-of-the-art systems utilize a sinusoidal excitation to drive superparamagnetic nanoparticles into the non-linear part of their magnetization curve, which creates a spectrum with a clear separation of direct feed-through and higher harmonics caused by the particles response. One challenge for rectangular excitation is the discrimination of particle and excitation signals, both broad-band. Another is the drive-field sequence itself, as particles that are not placed at the same spatial position, may react simultaneously and are not separable by their signal phase or shape. To overcome this potential loss of information in spatial encoding for high amplitudes, a superposition of shifting fields and drive-field rotations is proposed in this work. Upon close view, a system matrix approach is capable to maintain resolution, independent of the sequence, if the response to pulsed sequences still encodes information within the phase. Data from an Arbitrary Waveform Magnetic Particle Spectrometer with offsets in two spatial dimensions is measured and calibrated to guarantee device independence. Multiple sequence types and waveforms are compared, based on frequency space image reconstruction from emulated signals, that are derived from measured particle responses. A resolution of 1.0 mT (0.8 mm for a gradient of (−1.25,−1.25,2.5) T/m ) in x- and y-direction was achieved and a superior sensitivity for pulsed sequences was detected on the basis of reference phantoms.