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Medical Metrology

Department 8.1

Bachelor and Master projects

MR spectroscopic measurements of macromolecules in vivo for better modelling and quantification of macromolecular and metabolite signals in MR spectroscopy (master project)

The signal acquired with MR spectroscopy to measure concentrations of neurometabolites, always contains to a certain degree signals of macromolecules (e.g. lipids or proteins) as well. These macromolecular signals are, however, usually not easily resolved single peaks, such as the signals of many neurometabolites, but rather broad “bumps” that overlap with different metabolite signals. Therefore, they need to be accounted for when quantifying the metabolite signals. Commonly, all macromolecular signals are modelled together, assuming the ratios between different macromolecular concentrations are fixed. This, however, is an overly simplified model, since macromolecular concentrations vary between different brain regions and in certain diseases. This project aims at developing and validating a more flexible model for macromolecules to improve the quantification of MR spectroscopy data. For more information, please contact Opens window for sending emailAriane Fillmer.

Compensation of physiological motion for MR applications (batchelor or master project)

Breathing or the beating of the heart can lead to movement of organs in the human body. This physiological motion can strongly impair the quality of MR images. We develop novel approaches to minimise these motion artefacts and to ensure excellent diagnostic accuracy of MRI for a wide range of applications, such as quantitative cardiac MRI or PET-MR.

If you are studying physics, electrical engineering or a comparable area of engineering/natural sciences and you are interested in a summer project or BSc/MSc project in the field of motion compensation, please contact Christoph Kolbitsch (Dr. Christoph Kolbitsch).

Development of new excitation and coding techniques for speed measurement of blood flow on the ultra-high-field MR-tomograph (master project)

A magnetic resonance imaging (MRI) scanner allows not only to display anatomical images, but also to acquire temporally and spatially resolved blood velocity vector fields. Thereby, complex blood flows in vessels may be imaged. In the working group, ultra-high field MRI, we implement and test these techniques, e.g. on a 7 Tesla prototype scanner. The advantage of ultra-high field MRI scanners in comparison to clinical MRI scanners of 1.5 Tesla or 3 Tesla is a higher velocity measurement accuracy (due to a higher signal-to-noise ratio). Especially, quantities derived from velocity may thus be determined with higher accuracy.

The goal of the project is to develop new velocity imaging techniques especially for 7T tomography, to carry out test measurements of the developed methods, and finally conduct first in-vivo measurements. Working on this project conveys basic knowledge of MR physics and MR velocity quantification.

Qualifications

  • Studying physics, (electronical) engineering, medical technology, computer science or a similar course
  • Programming skills (preferably MATLAB or C/C++)
  • Interest in MR physics, fluid mechanics and biomedical applications

For more information, please contact Dr. Sebastian Schmitter (+49 030 3481-7767)

Advanced image reconstruction for MRI

Magnetic Resonance Imaging (MRI) is a versatile medical imaging technique which is widely used in clinical practice. In recent years, great advances have been made in the area of MR image reconstruction introducing novel concepts such as parallel imaging, compressed sensing or machine learning. We are working on novel concepts for speeding up MR image reconstruction utilizing GPUs or optimizing OpenMP implementations in close cooperation Prof Juurlink (TU Berlin, Embedded Systems Architecture). 

If you are studying physics, electrical engineering or a comparable area of engineering/natural sciences and you are interested in a summer project or BSc/MSc project in the field of advanced image reconstruction for MRI, please contact Christoph Kolbitsch (Opens window for sending email Dr. Christoph Kolbitsch).

Simulation based comparison of CP mode and 2-spokes pTx excitation in MRI for implant safety assessment (master thesis/Masterarbeit)

Background:

Wire-like metallic implants (e.g. pacemakers leads) can heat up at their tips during an MRI (magnetic resonance imaging) exam due to the used RF-field. As this can lead to serious injuries, patients with such implant are generally excluded from MRI, even if the imaging could be advantageous. Our group already demonstrated that a 2-spokes pTx (parallel transmission) approach is able to outperform static shimming methods like the common CP (circular polarization) excitation mode or an adjusted implant-friendly mode in terms of B1+ homogeneity and maximum SAR (specific absorption rate) at the implant tip for a PVP/water phantom, see Fig. 1.

Tasks:

Building on the existing simulation workflow consisting of finite difference time domain (FDTD) electromagnetic simulation, co-simulation and 2-spokes optimization, see Fig. 2, the successful applicant will perform simulations with virtual human phantoms at different MRI magnetic field strengths. A region of interest approach will be implemented for the 2-spokes excitation to achieve better selectivity. Finally, thermal simulations will validate whether the orders of magnitude lowered SAR at the implant tip outweigh the cost of increased SAR close to the body's surface.

Requirements:

- master student in physics or comparable
- fluent in English or German
- good programming skills, preferable in Python

Contact:

Johannes Petzold, Opens window for sending emailjohannes.petzold(at)ptb.de, phone: +49 30 3481 7364

Dr. Frank Seifert, Opens window for sending emailfrank.seifert(at)ptb.de, phone: +49 30 3481 7377

Contact

Address

Physikalisch-Technische Bundesanstalt
Abbestraße 2–12
10587 Berlin