Generating Electrical Impedance Tomographic Images from Electrical Phantoms in PSpice Circuit Simulator

Santa Catarina State University, Electrical Department, 89219-710 Joinville, SC, Brasil

^* Corresponding author: jerod.monteiro@edu.udesc.br
^** Corresponding author : pedro.bertemes@udesc.br

Abstract

Electrical Impedance Tomography (EIT) is an imaging technique that reconstructs the conductivity of biological tissues based on their electrical properties. The objective is to develop and validate, by PSpice simulations and image reconstructions by EIDORS, the mimicking electrical response of a biological material using 2,224 electrical components. It is built two different electrical phantoms by representing 32 electrodes. An injecting current of 35 mA across a pair of resistors at the edge of the phantom was used. A resistive phantom used resistors of 180 Ω for the mesh, and 128 resistors of 18 Ω to model low resistances areas, whereas 1.8 kΩ for high ones. The second phantom used 128 RC circuit elements of 1.8 kΩ (R) in parallel to 85 nF (C) to simulate an AC excitation from 1 to 100 kHz. The electrical phantoms represent both the mesh’s sensitivity to local conductivity variations and the edemas frequency-dependent behavior. The simulations were carried out using PSpice simulations, with image reconstruction performed in MATLAB and EIDORS. By visual inspections, the results indicated that the mesh responded adequately to the resistance change imposed to a particular area of the phantom in the frequency range from 1 to 100 kHz. It can be concluded that an electrical phantom model in SPICE simulator can mimic the tissue property variations, leading to an image of conductivity generated by software EIDORS.