The purpose of the research is to investigate the feasibility of a 1-0 imaging method utilizing Ultrasonic Vibration Potential (UVP). In this study, ultrasound is used as an external energy to vibrate charged particles or ions in colloids, producing electric dipole moments and generating electrical signals which are in relation to their properties. It is also expected that UVP can also be generated from biological colloids although very few studies involve the area of biological features were reported. The study was proposed with interest of revealing new feature of breast cancer in its earlier stages with the UVP technique, which is the ultimate goal of the research in a long term scope. As the initiation of the research, the main challenges and objectives of this study are to understand the theoretical foundation, establish the experimental methodology and conduct experimental verification for the potential of the technique to characterise particle, in terms of concentration and particle size, which would be the fundamental step of the investigation. This work begins with a critical review of the existing methods and equipment used for UVP measurement and the theoretical models. The O'Brien's local UVP theory with a slab model and an electric dipole model are verified and successfully applied to express the mechanism of UVP in the study. An experimental phantom with a specimen chamber and two types of signal sensors was designed. Effects of two types of sensors, in terms of the sensor in direct or indirect contact with the colloidal sample were investigated. Electrical signals were carefully verified on their sourcing locations. The intensity of measured UVP signals is in a range from 0.04 to 3.35 ~ in respect to silica suspensions with concentrations of 0.5-5%wt and various particle sizes. Trial tests on tumour cell lines were also conducted, which revealed the challenges in measuring biological cells. Ionic solutions were also tested with different concentrations of 2 mol/L and 3 mol/L respectively. Overall, this work demonstrates the feasibility and possibility of the technique in characterising concentration and particle size effects in particular to ionic solutions and colloids. Results are reported and existing challenges are addressed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:590270 |
| Date | January 2010 |
| Creators | Guan, Peng |
| Publisher | University of Leeds |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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