Calculation of Electrostatically Induced Current in a Human Body Simulated with the Curved-Element BEM

Abstract

The paper describes the calculation results of electrostatically induced current in a human model. The calculation method is the boundary element method (BEM). The human model was constructed from the second order curved elements. Five intenal organs were added to the model in order to investigate the effect of differences in conducivity values. The calculation results show that there is no effect of conductivity in the calculation of overall induced current. We have confirmed that the overall calculated induced current is about 15% higher than the empirical expression given by the EPRI. If we keep the height of the human model constant, 10% change in size of the model results in about 5.5% change in the overall induced current. The induced current was found almost uniformly distributed on each z cross section. In the human model with the internal organs, conductivity of internal organs exhibits considerable effect on their induced current. We have shown that the induced current in an organ varies proportionally to the ratio of its conductivity to the surrounding conductiviy if it is located separately from the other organs. We have compared induced electric field in an organ with an analytical solution in the arrangement of an ellipsoid in a uniform field. The difference between the analytical and numerical values is very small in the liver and intestine. However, the field distribution in the heart and lung varies so much along z-direction that the analytic solution is not a good approximation.