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Physik der biomedizinischen Bildgebung

Julia Herzen

Forschungsgebiet

Eine Beschreibung der faszinierenden Forschungsthemen folgt in Kürze.

Adresse/Kontakt

James-Franck-Str. 1
85748 Garching b. München

Mitarbeiterinnen und Mitarbeiter der Arbeitsgruppe

Professorinnen und Professoren

Mitarbeiterinnen und Mitarbeiter

Lehrangebot der Arbeitsgruppe

Lehrveranstaltungen mit Beteiligung der Arbeitsgruppe

Ausgeschriebene Angebote für Abschlussarbeiten an der Arbeitsgruppe

Energy response determination of photon-counting detectors

During the last years, computed tomography (CT) platforms were constantly enhanced in order to improve the image quality under simultaneous reduction of the radiation dose. An advancement of conventional CT, namely Dual-Energy CT  uses two different x-ray energy spectra in order to reduce prominent image artifacts and improve the image quality by a strong noise reduction compared to conventional CT devices. Current research in CT focuses on using even more than two different x-ray energy spectra in order to  further boost the performance of CT devices, which is named spectral CT.

However, the simultaneous acquisition of several x-ray spectra is only possible by the use of a novel detector technology namely photon-counting detector (PCD). Although first customer models of this technology are already available, current PCDs  are still far from fulfilling the high requirements that are demanded in a clinical CT system. A major problem thereby is the knowledge of the energy response of the detector systems, which however is essential for spectral CT. So far the determination of this energy response is mostly done at large scale synchrotron facilities which is very time-consuming and expensive.

This Master thesis project focuses on the development and evaluation of a new approach to determine the energy response of PCDs using a standard laboratory set-up with a conventional x-ray tube.  In the course of this project the student should optimize the new method and evaluate it with different detector systems.

After successful  determination of the energy response, the findings should be directly  applied to spectral imaging methods to evaluate the new approach and its practicality for a spectral CT system.

 

This thesis will be mostly about experimental work in the laboratory. However, for processing of the acquired data programming experience is recommended.

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Kern-, Teilchen- und Astrophysik
  • Masterarbeit Biophysik
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Julia Herzen
Spectral phase-contrast and darkfield imaging

This project combines two promising x-ray imaging techniques, namely spectral x-ray imaging and grating-based phase-contrast imaging.  In spectral x-ray imaging,  scans of an object are conducted with two or more different photon energy spectra. This can be realized with photon counting detectors, which are able to partially resolve the energy of the detected photons.  Contrary to conventional x-ray imaging, spectral imaging allows to retrieve information about the energy-dependent x-ray attenuation of the sample. On the other side, phase-contrast imaging is not based on an attenuation contrast but on the phase shift which an x-ray wavefront exhibits when passing through an object. Besides superior soft-tissue contrast, phase-contrast imaging also allows to extract a darkfield signal which provides information about the microstructure of the sample. In this project, we want to exploit the advantages of spectral and phase contrast imaging by combining a grating interferometer with an energy-resolving photon counting detector. The long-term aim of the underlying project is to design a CT system exploiting the combination of spectral imaging and phase contrast imaging. The master thesis project focuses on the experimental validation of the developed concepts and the respective processing algorithms on a stationary laboratory CT set-up. The findings of this work will directly contribute to the development of the novel CT system, which is currently in work.

 

This thesis will be about 50% experimental work in the laboratory and 50% algorithmic development and data processing. We are thus looking for a highly motivated student with experimental skills as well as programming experience.

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Kern-, Teilchen- und Astrophysik
  • Masterarbeit Biophysik
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Julia Herzen

Abgeschlossene und laufende Abschlussarbeiten an der Arbeitsgruppe

Stabilizing X-ray gratings with high aspect ratio for phase-contrast imaging
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Julia Herzen
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