Department of Radiology - Medical Physics

The Department of Radiology, Medical Physics is looking for a Bachelor Student in Physics/Engineering for

Transmission Lines for Measurement of Dielectric Parameters of Liquids

Magnetic Resonance Imaging (MRI) studies require an accurate knowledge of the electrical properties of tissues. In MRI-safety tests, dielectric properties of a phantom liquid must be consistent with that of the international standards. Measurement of permittivity and conductivity in radio frequency and microwave range is significant for electromagnetic dosimetry studies where realistic models for in-vivo electromagnetic energy exposures are simulated. We have developed reflection coefficient based measurement technique for lossy transmission line models to determine relative permittivity and conductivity simultaneously.

In this bachelor project, a coaxial line fixture for dielectric property measurement of phantom liquids will be constructed and the software for fitting the measured network analyser data will be improved by a graphical user interface. Additionally, an open-ended coaxial line sensor, or alternatively a monopole line probe will be designed for in vivo measurements of dielectric parameters based on a single measurement. Finally, both measurement methods will be compared and a look-up table will be created for phantom-ingredients (e.g. CuSO4­, NaCl, Agar etc.) vs. conductivity and permittivity values.

The successful candidate should have an interest and some experience in:   

• Microwave Theory
• Programming (C++, MATLAB)
• Mechanical Design

The starting date is negotiable. Please submit your application and documents (preferably by email) no later than June 30th to:

Dr. Ali Caglar Özen
ali.oezen@uniklinik-freiburg.de  

Prof. Dr. Michael Bock
Professor for Experimental Radiology
michael.bock@uniklinik-freiburg.de

Universitätsklinikum Freiburg
Radiologische Klinik - Medizin Physik
Breisacher Straße 60a 79106 Freiburg  

Publication date: 29 May 2017

The Hyperpolarization Group is searching for a Physics Master student for a project on

Hyperpolarized 13C-tracers produced in a commercial MRI system.

Nuclear hyperpolarization is an emerging method to increase the signal of magnetic resonance (MR) by several orders of magnitude. In fact, all modern MRI scanners use only a few parts per millions of the signal that is theoretically available. Hyperpolarization commences at the very fundamentals of MR by increasing the inherent low polariaztion up to unity.

One application, e.g., is the production of novel magnetically labled molecules (hyperpolarized tracers). However, current methods for the production of hyperpolarized 13C-tracers require a dedicated, complex and costly polarizer device.

Recently, we developed a new method that enables 13C-hyperpolarization >20% and ex-vivo 13C-MRI without an external polarizer, but by using the hardware of an MRI system instead.  The tracer is produced near the application site and subsequent 13C-MRI is possible without transfer of the sample, at a fraction of the cost and complexity of external polarizers.

The aim of this thesis is the implementation of the method on a 3 Tesla Siemens MRI system and further analysis of the underlying physics.

The applicant will be directly supervised by Dipl.-Phys. Andreas Schmidt and M.Sc. Stephan Berner in the department for Medical Physics of Prof. Hennig.

For further information please inquire at or send an informal application with CV and few sentences about you and your course of studies to Andreas Schmidt (andreas.schmidt@uniklinik-freiburg.de)

Publication date: 29 Nov. 2016

We are looking for a Master student in Physics to support our project on

Dental Magnetic Resonance Imaging (MRI).

Dental MRI is a highly interesting application of MRI that holds great promise for routine and scientific application.

The project we offer is highly interesting and interdisciplinary, bridging the gap between fundamental physics (high-frequency electronics, spin manipulations) and clinical application (imaging of healing processes e.g.). The project comprises the development of new methods for dental MRI as well as the acquisition of human data in vivo. These methods comprise new hardware developments (MRI coils), optimization of MR-sequences for the given task, and the exploration of new sequence approaches (e.g. ultra-short echo time (UTE) MRI).

The project is up-and-running and a plethora of results are being produced. We are offering two positions to motivated students who would like to pursue their Master thesis in Physics on this subject. The applicant will be directly supervised by Dr. rer. nat. Jan-Bernd Hövener and Dr. rer. nat. Ute Ludwig in the department for Medical Physics of Prof. Hennig in collaboration with the clinic of maxillofacial surgery.

Please send your application, including a CV and report of your grades, to:
Dr. Jan-Bernd Hövener, jan.hoevener@uniklinik-freiburg.de

_{Publication date: 29 Nov. 2016}