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A D-bar method for recovering admittivity in 2-D electrical impedance tomography.

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Author(s):
Claudia Natalia Lara Herrera
Total Authors: 1
Document type: Doctoral Thesis
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Escola Politécnica (EP/BC)
Defense date:
Examining board members:
Raúl González Lima; Joyce da Silva Bevilacqua; Jennifer Lynn Mueller; Helcio Rangel Barreto Orlande; Clodoaldo Grotta Ragazzo
Advisor: Raúl González Lima; Jennifer Lynn Mueller
Abstract

This work proposes a new D-bar method of Electrical Impedance Tomography (EIT) for reconstructing the conductivity and permittivity simultaneously in a 2-D domain. The direct algorithm presented is based on the existence and uniqueness proof by E. Francini [1]. Biological tissue characterization is strongly facilitated by the knowledge of its electric properties. In EIT medical applications there is great interest in the permittivity as an additional property for distinguishing pathologies. For instance, the determination of presence or absence of blood in fluid accumulation in the lung. Numerical and experimental data tests are carried out in order to verify and understand the properties, capabilities and limitations of the implemented algorithm. A numerical phantom to solve the forward admittivity problem is developed which allows to simulate voltage data sets. Trigonometric and pairwise injection current patterns are applied. Exponentially growing solutions of the inverse problem are a key part of the algorithm, which have to be expanded in terms of the current patterns. Understanding the nature of these expansions for trigonometric and pairwise injection current patterns leads to a set of specifications in the design of an EIT system for this algorithm. The encouraging numerical and experimental results obtained in conductivity and permittivity reconstructions, regarding the magnitude and spatial resolution, indicate that the algorithm is promising for clinical use. (AU)

FAPESP's process: 08/08739-7 - A D-bar method for imaging admittivity in 2D by Electrical Impedance Tomography.
Grantee:Claudia Natalia Lara Herrera
Support type: Scholarships in Brazil - Doctorate