Boundary element method and internal electrodes in electrical impedance tomography

Traditionally in electrical impedance tomography an approximation for the internal resistivity distribution is computed based on the knowledge of the injected currents and measured voltages on the surface of the object. However, in certain applications it is also possible to use internal current sources and voltage measurements. In this paper we propose a boundary element-based method which utilizes data also from internal electrodes in the image reconstruction. The proposed approach assumes that the internal geometry is known a priori and only the conductivities of the predetermined regions are estimated. Two-dimensional simulations with four additional sources=measurement locations show clear improvement in the reconstructed images when the results are compared to those based only on boundary data