Ultrasound

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					Ultrasound sensor for biomedical application

Background:
In hyperthermia treatment of breast-/chest wall cancer, microwaves are used to heat up
the body tissue in the range of 41-45ºC at depth while microwave radiometry can be used
to monitor the temperature of the heated tissue. These microwave techniques are both
non-invasive and provides no or only mild discomfort for the patient, and have been
shown to significantly increase the response rate for radiation therapy or/and
chemotherapy. Between the microwave antennas and the skin, we have to use a water
bolus to control the skin temperature. The water bolus thickness has a large effect of the
microwave propagation, and it is very important to know this thickness both to adjust the
applied power and to calibrate the temperature measurements.

Project outline:
Design an ultrasound sensor to measure the water bolus thickness. The sensor is to be
located in the center of a microwave antenna, which in practice means that it has to be
fitted in a hole of a printed circuit board. Standard ultrasound transducer may be
considered if their size and sensitivity permits, but it is likely that an optimal design using
PVDF film give better results. The built prototype sensor has to be evaluated in terms of
range accuracy and robustness.

Required courses:
   - FYS1006: Introduction to signals and sensors
   - FYS2006: Signal processing
   - FYS2008: Measurement techniques
   - FYS3007: Microwave techniques (optional)

Relevance:
   1) A successful outcome of this project will probably be applied in a clinical system
      at Duke University Medical Center, North Carolina, USA. It may be possible with
      a 2-6 weeks stay at this institution as part of or after the master thesis.
   2) The ultrasound sensor design in this project fits well into the large ultrasound
      project at the Department of physics and technology, University of Tromsø, in
      which both Prof. Frank Melandsø and Prof. Svein Jacobsen are strategically
      involved.
   3) Another possible application of this sensor is to measure the different soft tissue
      layers inside the body. Getting the skin and fat thickness in front of the bladder,
      it’s possible to make a more accurate temperature model for the bladder
      temperature. ThermImage, a start-up company located in Salt Lake City, has
      recently patented a device for microwave heating of bladder to be used for
      detection of vasicoureteral reflux (VUR) in pediatric patients. Associate professor
      Yngve Birkelund has been in collaboration with ThermImage during his
      sabbatical stay at Duke, and ThermImage would be very happy to include a
      similar sensor for their system.

Supervisor: Yngve Birkelund

				
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posted:12/1/2011
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