ELECTRICAL IMPEDANCE TOMOGRAPHY IN THREE DIMENSIONS

Abstract

An algorithm is developed for electrical impedance tomography (EIT) of three-dimensional volumes using multi-planar electrode arrays. This algorithm is based upon the method of least squares, and uses one step of Newton's method to estimate the conductivity distribution inside the volume using electrical measurements made on the boundary. An implementation of the algorithm for right cylindrical volumes is described. This computer code, called N3D, permits reconstructions with up to 2016 degrees of freedom. The code uses an initial guess consisting of uniform conductivity, allowing many of the computations to be done analytically. Although the code does not reconstruct the conductivity distribution accurately (unless it differs very little from a constant), it does yield useful images at reasonable computational cost. The algorithm is demonstrated using three-dimensional resistivity distributions reconstructed from experimental data. [Vol. 7, No. 2, pp. 128-147 (1992), Special Issue on Bioelectromagnetic Computations]