Ultrasonic vibration potential imaging: Theory and experiment

This thesis aims to elaborate the theory of ultrasonic vibration potential imaging as well as to propose and implement new electro-acoustic imaging methodology for biomedical applications based on ultrasonic vibration potential.;Ultrasonic vibration potential refers to an electric signal developed across a colloidal or ionic solution with a presence of ultrasound. In colloidal suspensions, the vibration potential is generated as a consequence of the different motions of the colloidal particles and the solvent under the alternating acceleration in a sound wave. Upon passage of a sound wave, the normally spherical distribution of counter charge around those particles is periodically distorted resulting in the formation of dipoles at the sites of the colloidal particles. These dipoles add over a macroscopic distance to form a voltage. Thus, if electrodes are placed in the solution, an alternating voltage can be detected.;Since possessing electrolytes and containing red blood cells, whole blood is both colloidal and ionic. Experiments have shown that the whole canine blood produces vibration potentials on the order of about 500 times as large as those from various muscle tissues, which points to application of any biological or medical problem that requires blood detection. This thesis focuses on the detailed analytical explanation and theories of both the generation of current and the distribution of potential and electric field inside colloidal solutions. Experiments with different methodologies and samples were conducted to not only give results in an excellent agreement with the theory but also help proposing and implementing a new imaging method using ultrasonic vibration potential.