Dr.-Ing. Matthias Gräser

Universitätsklinikum Hamburg-Eppendorf (UKE)
Sektion für Biomedizinische Bildgebung
Lottestraße 55
2ter Stock, Raum 212
22529 Hamburg

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

Tel.: 040 / 7410 25812
E-Mail: matthias.graeser(at)tuhh.de
E-Mail: ma.graeser(at)uke.de

Research Interests

  • Magnetic Particle Imaging
  • Low Noise Electronics
  • Inductive Sensors
  • Passive Electrical Devices

Curriculum Vitae

Matthias Gräser submitted his Dr.-Ing. thesis in january 2016 at the institute of medical engineering (IMT) at the university of Lübeck and is now working as a Research Scientist at the institute for biomedical imaging (IBI) at the technical university in Hamburg, Germany.  Here he develops concepts for Magnetic-Particle-Imaging (MPI) devices. His main aim is to improve the sensitivity of the imageing devices and improve resolution and application possibilities of MPI technology.

In 2011 Matthias Gräser started to work at the IMT as a Research Associate in the Magnetic Particle Imaging Technology (MAPIT) project. In this project he devolped the analog signal chains for a rabbit sized field free line imager. Additionally he developed a two-dimensional Magnetic-Particle-Spectrometer. This device can apply various field sequences and measure the particle response with a very high signal-to-noise ratio (SNR).

The dynamic behaviour of magnetic nanoparticles is still not fully understood. Matthias Gräser investigated the particle behaviour by modeling the particle behaviour with stochastic differential equations. With this model it is possible to simulate the impact of several particle parameters and field sequences on the particle response .

In 2010 Matthias Gräser finished his diploma at the Karlsruhe Institue of Technology (KIT). His diploma thesis investigated the nerve stimulation of magnetic fields in the range from 4 kHz to 25 kHz.

Journal Publications

[76875]
Title: Signal separation in magnetic particle imaging.
Written by: M. Graeser, T. Knopp, T. F. Sattel, M. Grüttner, and T. M. Buzug
in: <em>{IEEE} Nuclear Science Symposium and Medical Imaging Conference ({NSS}/{MIC})</em>. (2012).
Volume: Number:
on pages: 2483--2485
Chapter:
Editor:
Publisher:
Series:
Address:
Edition:
ISBN:
how published:
Organization:
School:
Institution:
Type:
DOI: 10.1109/NSSMIC.2012.6551566
URL:
ARXIVID:
PMID:

[BibTex]

Note: inproceedings

Abstract: Magnetic particle imaging ({MPI}) applies oscillating magnetic fields to measure the distribution of magnetic nanoparticles in-vivo. Using receive coils, the change of the particle magnetization can be detected. However, the signal induced by the nanoparticles is superimposed by the signal induced by the sinusoidal excitation field, which directly couples into the receive coils. As the latter is several magnitudes higher, the separation of the particle signal from the excitation signal is a challenging task. One way to remove the excitation signal from the induced voltage in the receive coil is to suppress the excitation signal at its base frequency by means of a band-stop filter. An alternative is to recover the particle signal by compensating the excitation signal in the receive chain, which allows recovering the particle signal at its full bandwidth. In this work, it is proposed to combine both methods which allows increasing the dynamic range of the recorded signal while still recovering the fundamental frequency.

Conference Proceedings

[76875]
Title: Signal separation in magnetic particle imaging.
Written by: M. Graeser, T. Knopp, T. F. Sattel, M. Grüttner, and T. M. Buzug
in: <em>{IEEE} Nuclear Science Symposium and Medical Imaging Conference ({NSS}/{MIC})</em>. (2012).
Volume: Number:
on pages: 2483--2485
Chapter:
Editor:
Publisher:
Series:
Address:
Edition:
ISBN:
how published:
Organization:
School:
Institution:
Type:
DOI: 10.1109/NSSMIC.2012.6551566
URL:
ARXIVID:
PMID:

[BibTex]

Note: inproceedings

Abstract: Magnetic particle imaging ({MPI}) applies oscillating magnetic fields to measure the distribution of magnetic nanoparticles in-vivo. Using receive coils, the change of the particle magnetization can be detected. However, the signal induced by the nanoparticles is superimposed by the signal induced by the sinusoidal excitation field, which directly couples into the receive coils. As the latter is several magnitudes higher, the separation of the particle signal from the excitation signal is a challenging task. One way to remove the excitation signal from the induced voltage in the receive coil is to suppress the excitation signal at its base frequency by means of a band-stop filter. An alternative is to recover the particle signal by compensating the excitation signal in the receive chain, which allows recovering the particle signal at its full bandwidth. In this work, it is proposed to combine both methods which allows increasing the dynamic range of the recorded signal while still recovering the fundamental frequency.