A numerical model for magnetic induction tomographic measurements in biological tissues

A finite-difference model has been developed for simulating measurements in magnetic induction tomography (MIT) for biological tissues. The model has three stages: (1) computation of the distribution of current induced in a volume of dielectric due to the magnetic field from an excitation coil; both the electrical conductivity and permittivity of the dielectric are taken into account: (2) computation of the e.m.f. induced in the sensing coil directly from the excitation coil; (3) computation of the e.m.f. induced in a sensing coil due to the current distribution in the dielectric. From the results of stages (2) and (3), the change in signal in the sensing coil due to the dielectric can be obtained, in magnitude and phase, as a fraction of the signal received in the absence of the dielectric. The peak values in the modelled curves agreed to within 14% of practical measurements at 10 MHz on volumes of saline solution with conductivities in the range 0.7 to 6 S m(-1).