Preamplifier Noise Figure Measurement and Radio Frequency Field Optimization in High Field Magnetic Resonance Imaging

• Author / Creator

  Lagore, Russell Luke

• High field magnetic resonance imaging (MRI) is an area of research interest due to the associated improvement in image quality possible. This improvement comes at a cost. Hardware design becomes more complex in order to overcome technical challenges at these higher field strengths. Signal-to-noise ratio is of paramount importance to MR image quality and this comes from carefully designed hardware and pulse sequences.
  This thesis focuses on the radiofrequency hardware of a high field MRI system. As frequency increases, the difficulties associated with radiofrequency hardware design increase.
  A noise figure and noise parameter measurement system was developed for measurement of the noise added by measurement electronics in MRI. Noise figure was found to increase for many transistor semiconductors as magnetic field increased.
  The radiofrequency transmit field was also studied. Radiofrequency hardware was modified to optimize the radiofrequency field to achieve proper contrast in MR images and improve transmit power efficiency.

• Subjects / Keywords

  • Radio frequency field
  • Preamplifier noise parameters
  • High field magnetic resonance imaging
  • Noise figure
  • High field radio frequency hardware

• Graduation date

  Fall 2013

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3BD50

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.