Three-dimensional electrical impedance tomography using complete electrode model

In Electrical Impedance Tomography (EIT) 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 body. It is often assumed that the injected currents are confined to the 2D electrode plane and the reconstruction is based on the 2D assumptions. However, the currents spread out in three dimensions and therefore off-plane structures have significant effect on the reconstructed images. In this paper we propose a finite element-based method for the reconstruction of 3D resistivity distributions. Both the forward and the inverse problems are discussed and the results from reconstructions with simulated an real measurement data are presented. The proposed method is based on the so-called complete electrode model that takes into account the presence of the electrodes and the contact impedances. This makes it possible to apply the proposed method also for static EIT with complicated geometries.