Computation of electrostatic fields in anisotropic human tissues using the Finite Integration Technique (FIT)

摘要

The exposure of human body to electromagneticfields has in the recent years become a matter of great interestfor scientists working in the area of biology and biomedicine.Due to the difficulty of performing measurements,accurate models of the human body, in the form of a computerdata set, are used for computations of the fields insidethe body by employing numerical methods such as themethod used for our calculations, namely the Finite IntegrationTechnique (FIT). A fact that has to be taken intoaccount when computing electromagnetic fields in the humanbody is that some tissue classes, i.e. cardiac and skeletalmuscles, have higher electrical conductivity and permittivityalong fibers rather than across them. This property leads todiagonal conductivity and permittivity tensors only when expressingthem in a local coordinate system while in a globalcoordinate system they become full tensors. The Finite IntegrationTechnique (FIT) in its classical form can handle diagonallyanisotropic materials quite effectively but it neededan extension for handling fully anisotropic materials. Newelectric voltages were placed on the grid and a new averagingmethod of conductivity and permittivity on the grid wasfound. In this paper, we present results from electrostaticcomputations performed with the extended version of FITfor fully anisotropic materials.