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

[76871]
Title: SNR and Discretization Enhancement for System Matrix Determination by Decreasing the Gradient in Magnetic Particle Imaging.
Written by: M. Graeser, A. von Gladiss, T. Friedrich, and T. M. Buzug
in: <em>International Journal on Magnetic Particle Imaging</em>. (2017).
Volume: <strong>3</strong>. Number: (1),
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URL: https://journal.iwmpi.org/index.php/iwmpi/article/view/97
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[www] [BibTex]

Note: article

Abstract: In system matrix (SM) based reconstruction, the physical resolution is often within the range of the SM discretization. This is caused by the signal to noise ratio (SNR) decrease following a discretization increase due to the smaller particle sample volume. As the SNR affects the resolution of the image as well, it is necessary to decouple the SNR and discretization. In this work, a calibration protocol is presented which enhances either the SNR or discretization by reducing the gradient strength within the system calibration. This new protocol results in higher resolution and better image quality.

Conference Proceedings

[76871]
Title: SNR and Discretization Enhancement for System Matrix Determination by Decreasing the Gradient in Magnetic Particle Imaging.
Written by: M. Graeser, A. von Gladiss, T. Friedrich, and T. M. Buzug
in: <em>International Journal on Magnetic Particle Imaging</em>. (2017).
Volume: <strong>3</strong>. Number: (1),
on pages:
Chapter:
Editor:
Publisher:
Series:
Address:
Edition:
ISBN:
how published:
Organization:
School:
Institution:
Type:
DOI:
URL: https://journal.iwmpi.org/index.php/iwmpi/article/view/97
ARXIVID:
PMID:

[www] [BibTex]

Note: article

Abstract: In system matrix (SM) based reconstruction, the physical resolution is often within the range of the SM discretization. This is caused by the signal to noise ratio (SNR) decrease following a discretization increase due to the smaller particle sample volume. As the SNR affects the resolution of the image as well, it is necessary to decouple the SNR and discretization. In this work, a calibration protocol is presented which enhances either the SNR or discretization by reducing the gradient strength within the system calibration. This new protocol results in higher resolution and better image quality.