A scanning rheo-magneto-acoustic method of current imaging in volume conductors

Abstract

It can be shown that acoustic waves are generated when oscillating magnetic fields are applied to tissue supporting ionic current flows. These acoustic waves result from predictable and relatively well understood Lorentz forces. At microampere biological current levels and with 1-kHz and 0.2-T magnetic fields, the forces are on the order of 10/sup -10/ N and thus the acoustic responses are weak but rapidly detectable using microphones in small objects. This principle has been used in conjunction with a magnetic field scanning system to produce images of the flow of ion currents in 2 cm*2 cm*3 mm conductors.<>