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Travelling Wave Systems

The main goal of this project is to investigate the installation of travelling wave systems on a 9.4T whole-body MR-PET scanner. Given the absence of a body coil, we wish to employ the integrated radio-frequency screen as a circular waveguide. The length and the inner diameter of the screen are 1220 mm and 684 mm, respectively. For an air-filled circular waveguide with these dimensions, the dominant TE11- and the TM01-mode can be excited. In contrast to the default signal excitation and reception with one or multiple radio-frequency resonators, the signal excitation and reception should be done with travelling waves. Thus, new excitation devices, e.g., antennas, are required. The first prototype of an excitation device designed in-house is a circular polarised patch antenna.

Test of different patch positions relating to the waveguide:

  • variation of the coupled power
  • variation of the coupled power
  • SAR distribution in different loads (see Fig.1)

Multi-mode excitation and reception:

  • development and realisation of new excitation devices
  • Use of pTX hardware

SAR DistributionFig.1: SAR-distribution in the y-plane of a virtual human model during travelling wave excitations