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

[76909]
Title: Imaging Characterization of {MPI} Tracers Employing Offset Measurements in a two Dimensional Magnetic Particle Spectrometer.
Written by: D. Schmidt, M. Graeser, A. von Gladiss, T.M. Buzug, and U. Steinhoff
in: <em>International Journal on Magnetic Particle Imaging</em>. (2016).
Volume: <strong>2</strong>. Number: (1),
on pages:
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DOI: 10.18416/ijmpi.2016.1604002
URL: https://journal.iwmpi.org/index.php/iwmpi/article/view/24
ARXIVID:
PMID:

[www] [BibTex]

Note: article

Abstract: We developed a method to characterize the imaging performance of {MPI} tracers from virtual {MPI} measurements that can be synthesized using measurement data from a Magnetic Particle Spectrometer ({MPS}) at different static magnetic field offsets. {MPI} system functions were obtained from measurements on a {FeraSpin}™ R ({nanoPET} {GmbH}, Berlin) sample in a 2D {MPS} comprising two excitation coils and two receive coils. Software phantoms of spatial {MPI} tracer distributions with different size and shape were constructed. With the measured {MPI} system function, a synthetic {MPI} measurement of the software phantoms was simulated. By adding noise to the virtual {MPI} data, the detection limit of each harmonic in dependence of the noise level was obtained. An {MPI} reconstruction of the virtual tracer distribution was performed using the virtual {MPI} data as input. By comparing the reconstructed images with the actual software phantoms, we obtained the spatial resolution of {MPI} of the investigated tracers. This method might help predicting the image resolution for real {MPI} setups. Our characterization method provides a valuable link between pure spectroscopic characterization and time consuming {MPI} phantom experiments.

Conference Proceedings

[76909]
Title: Imaging Characterization of {MPI} Tracers Employing Offset Measurements in a two Dimensional Magnetic Particle Spectrometer.
Written by: D. Schmidt, M. Graeser, A. von Gladiss, T.M. Buzug, and U. Steinhoff
in: <em>International Journal on Magnetic Particle Imaging</em>. (2016).
Volume: <strong>2</strong>. Number: (1),
on pages:
Chapter:
Editor:
Publisher:
Series:
Address:
Edition:
ISBN:
how published:
Organization:
School:
Institution:
Type:
DOI: 10.18416/ijmpi.2016.1604002
URL: https://journal.iwmpi.org/index.php/iwmpi/article/view/24
ARXIVID:
PMID:

[www] [BibTex]

Note: article

Abstract: We developed a method to characterize the imaging performance of {MPI} tracers from virtual {MPI} measurements that can be synthesized using measurement data from a Magnetic Particle Spectrometer ({MPS}) at different static magnetic field offsets. {MPI} system functions were obtained from measurements on a {FeraSpin}™ R ({nanoPET} {GmbH}, Berlin) sample in a 2D {MPS} comprising two excitation coils and two receive coils. Software phantoms of spatial {MPI} tracer distributions with different size and shape were constructed. With the measured {MPI} system function, a synthetic {MPI} measurement of the software phantoms was simulated. By adding noise to the virtual {MPI} data, the detection limit of each harmonic in dependence of the noise level was obtained. An {MPI} reconstruction of the virtual tracer distribution was performed using the virtual {MPI} data as input. By comparing the reconstructed images with the actual software phantoms, we obtained the spatial resolution of {MPI} of the investigated tracers. This method might help predicting the image resolution for real {MPI} setups. Our characterization method provides a valuable link between pure spectroscopic characterization and time consuming {MPI} phantom experiments.