The Two Dimension Finite Element Method Simulation to Determine the Brain Capacitance Based on ECVT Measurements
Syarif Hussein Sirait, MS Thesis, Dept. of Physics, Bandung Institute of Technology, 2015
This study aimed to simulate the capacitance value of 2D brain geometry based on two electrodes ECVT measurements using finite element method. ECVT (electrical capacitance volume tomography) is a tomography modality which produces a dielectric distribution image of a subject from several electrodes that measure capacitance. The simulation was performed in COMSOL Multiphysics which is a finite element method software. This study began with construction of 2D brain geometry domain and ECVT sensor design. After that, boundary conditions were applied on two electrodes in the sensor domain. Since the real ECVT system measurement used sinusoidal signal with 20 V in potential and 2.5 MHz frequency then the first boundary is defined as a Dirichlet boundary condition with 20 V potential and 2.5 MHz frequency sinusoidal signal and the other boundary is defined as a Dirichlet boundary condition with 0 V. Poisson equation was implemented as the governing equation in the 2D brain geometry. Finite element method was used to solve the Poisson equation. Hodgkin-Huxley
action potential assumed as the electrical activity in the brain was applied as disturbance potential in the geometry. In this study, two models of potential distribution has been generated, the potential distribution without disturbance and potential distribution with disturbance. After achieving potential distributions, the capacitances of each potential distribution are determined.
Keyword: ECVT, finite element method, brain capacitance simulation, brain activity.