Indirect calculation of breast tissue impedance values

One of the problems facing anyone attempting the investigation of dielectric properties of living tissue is the presence of skin, which screens all that lies under it from direct measurement. Thus, in non-invasive breast examination using transimpedance measurements, skin parameters heavily influence the results, specifically at low (less than 10 kHz) frequencies. In this paper a method for overcoming this difficulty by using multi-frequency measurements obtained from a surface current distribution over a flat probe is described. By using the variation in the shape of the real and imaginary parts of the surface current density at different frequencies, the original dielectric values of the skin and the underlying tissue can be obtained, based on the assumption of the existence of a two-layer geometry, with the upper (skin) layer much thinner than the lower (tissue) layer. The results obtained can be used in the diagnosis of breast cancer using existing transimpedance measurement devices.