Targeted imaging with microbubbles may resolve the molecular expression within the abnormal blood vessels of tumours. Optimal imaging requires understanding the interaction between targeted microbubbles and high-frequency ultrasound. Therefore, the subharmonic signal, and backscattering cross-section of individual bound microbubbles were examined with coaligned 30 MHz pulses and optical images. The peak subharmonic signal was generated for 1.6 µm diameter microbubbles for 20% and 11% bandwidth pulses and 1.8 µm for 45% bandwidth pulses at 200 kPa, consistent with estimations of the resonant size of microbubble's at 15 MHz. In order to measure the scattering cross-section, a new method was proposed to measure the receive transfer function of a transducer. Measurements of the backscattering cross-section scaled with the square of the radius, with signi cant size-independent variability. The results of this thesis will help optimise the parameters for targeted imaging, as well as further our understanding of the behaviour of microbubbles.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/18889 |
| Date | 15 February 2010 |
| Creators | Sprague, Michael |
| Contributors | Foster, F. Stuart |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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