Estimation of multilayer tissue conductivities and structures using divided electrodes

To estimate inner multi-layer tissue structures and conductivities distribution in a cross section of the local tissue by using bioresistance data measured noninvasively, a new measurement method using divided electrodes is provided, in which current electrodes are divided into several parts. Our purpose is to assess the effects of the new method by computer simulations using a typical two-dimension (2D) model. Conductivity distributions and structure of the simplified (2D) model are analyzed based on a combination of a finite difference method (FDM) and a steepest descent method (SDM). Simulation results demonstrate that conductivity values of multi-layer tissue (skin, fat, muscle) can be estimated with an error less than 0.1%. Different strength random noise is added to measure resistance values, estimations of conductivity values for skin, fat and muscle are still reasonable precise. Optimal configuration for such divided electrodes is examined in terms of dividing pattern.