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

Journal Publications

[183660]
Title: Using Negative Bolus in Dynamic MPI.
Written by: F. Mohn, M. Exner, P. Szwargulski, M. Möddel, T. Knopp, and M. Graeser
in: <em>International Journal on Magnetic Particle Imaging IJMPI</em>. mar (2023).
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on pages: 9.(1).
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DOI: 10.18416/IJMPI.2023.2303022
URL: https://journal.iwmpi.org/index.php/iwmpi/article/view/579
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[www] [BibTex]

Note: inproceedings

Abstract: In Magnetic Particle Imaging, the spatial distribution of a tracer is measured and depicted with a concentration dependent signal intensity for any location that inhibits particles, whereas surrounding tissue does not provide any signal. After tracer injection, the signal over time (positive contrast) can be utilized as a transient response to calculate dynamic diagnostic parameters like perfusion parameter maps. In this work, a bolus of physiological saline solution without any particles (negative contrast) is proposed, where the remaining steady state concentration contributes to the image contrast. This opens up the possibility to stretch the total monitoring time of a patient by utilizing a positive-negative contrast sequence, while keeping the total iron dose constant in the subject. Resulting time responses show that normalized signals from positive and negative boli are concurrent in the phantom experiments, indicating identical diagnostic parameters for in-vivo use.

Conference Proceedings

Conference Proceedings

[183660]
Title: Using Negative Bolus in Dynamic MPI.
Written by: F. Mohn, M. Exner, P. Szwargulski, M. Möddel, T. Knopp, and M. Graeser
in: <em>International Journal on Magnetic Particle Imaging IJMPI</em>. mar (2023).
Volume: Number:
on pages: 9.(1).
Chapter:
Editor:
Publisher:
Series:
Address:
Edition:
ISBN:
how published:
Organization:
School:
Institution:
Type:
DOI: 10.18416/IJMPI.2023.2303022
URL: https://journal.iwmpi.org/index.php/iwmpi/article/view/579
ARXIVID:
PMID:

[www] [BibTex]

Note: inproceedings

Abstract: In Magnetic Particle Imaging, the spatial distribution of a tracer is measured and depicted with a concentration dependent signal intensity for any location that inhibits particles, whereas surrounding tissue does not provide any signal. After tracer injection, the signal over time (positive contrast) can be utilized as a transient response to calculate dynamic diagnostic parameters like perfusion parameter maps. In this work, a bolus of physiological saline solution without any particles (negative contrast) is proposed, where the remaining steady state concentration contributes to the image contrast. This opens up the possibility to stretch the total monitoring time of a patient by utilizing a positive-negative contrast sequence, while keeping the total iron dose constant in the subject. Resulting time responses show that normalized signals from positive and negative boli are concurrent in the phantom experiments, indicating identical diagnostic parameters for in-vivo use.