Multi frequency electrical impedance tomography

Electrical impedance tomography (EIT) is a non-invasive method to monitor c onductivity changes in regions of the human body. Its robust, miniaturizabl e instrumentation makes EIT particularly suitable for online-monitoring wit hout too much inconvenience for the patient. A major methodological problem is the poor quality of the conductivity images, which is due to the low sp atial resolution and low sensitivity for structures far away from the objec t's surface as well as large qualitative errors in the reconstructed conduc tivity values. This paper outlines the advantages of multi-frequency EIT fo r a simple two-dimensional model In the first Part of the paper we assume t hat some a priori information from MR images is at hand, providing good sta rting values for the reconstruction process, while in the second part it is assumed that no a priori information about regions of different material v alues is available.