Magneto-acousto-electrical tomography : a potential imaging method for current density and electrical impedance

This thesis is about investigating a potential imaging modality, magneto-acousto-electrical tomography (MAET), to provide high-spatial-resolution images of lead field current density and electrical impedance of biological tissues. A lead field current density distribution is the one obtained when a current/voltage source is applied to a sample via a pair of electrodes. The lead field current density distribution can potentially be used to obtain electrical impedance distribution which is helpful in differentiating normal and cancerous tissues. To image lead filed current density, instead of directly applying a current/voltage source to the sample, the sample is placed in a static magnetic field and an ultrasound is focused on it to simulate a point like current dipole source in the focal zone. Electrodes are used to detect the voltage/current generated by the ultrasound in the sample, which according to the reciprocity theorem is proportional to a component of the lead field current density.