Magneto-acousto-electrical tomography: A new imaging modality for electrical impedance

Abstract

To provide high-spatial-resolution impedance information, we developed a new imaging method that we call Magneto-Acousto-Electrical-Tomography (MAET). First, we mapped the current density distribution Jab that would exist in a sample if a current/voltage source were to be applied to the sample through measurement electrodes a and b. Second, having mapped Jab we could calculate the electrical impedance of the sample. To map Jab(r) experimentally without applying a current/voltage source, we placed the sample in a static magnetic field and focused an ultrasonic pulse at r to simulate a point-like current dipole source at that point. Then through the electrodes we measured the voltage/current signal which, based on the reciprocity theorem, is proportional to a component of Jab(r). To map Jab over various r, the ultrasound beam was scanned throughout the sample. The electrical impedance could then be reconstructed from Jab. We will present the formulae for both the forward and inverse of MAET, as well as the experimental setup, methods, and results. © Springer-Verlag 2007.