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Computational and Mathematical Methods in Medicine
Volume 2013, Article ID 964918, 9 pages
http://dx.doi.org/10.1155/2013/964918
Research Article

A Local Region of Interest Imaging Method for Electrical Impedance Tomography with Internal Electrodes

1Department of Computational Science and Engineering, Yonsei University, Seoul 120-749, Republic of Korea
2The School of Electrical and Information Engineering, The University of Sydney, Sydney NSW 2006, Australia
3Impedance Imaging Research Center and Department of Biomedical Engineering, Kyung Hee University, Yongin 446-701, Republic of Korea

Received 13 November 2012; Revised 1 June 2013; Accepted 10 June 2013

Academic Editor: Bill Lionheart

Copyright © 2013 Hyeuknam Kwon et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Electrical Impedance Tomography (EIT) is a very attractive functional imaging method despite the low sensitivity and resolution. The use of internal electrodes with the conventional reconstruction algorithms was not enough to enhance image resolution and accuracy in the region of interest (ROI). We propose a local ROI imaging method with internal electrodes developed from careful analysis of the sensitivity matrix that is designed to reduce the sensitivity of the voxels outside the local region and optimize the sensitivity of the voxel inside the local region. We perform numerical simulations and physical measurements to demonstrate the localized EIT imaging method. In preliminary results with multiple objects we show the benefits of using an internal electrode and the improved resolution due to the local ROI image reconstruction method. The sensitivity is further increased by allowing the surface electrodes to be unevenly spaced with a higher density of surface electrodes near the ROI. Also, we analyse how much the image quality is improved using several performance parameters for comparison. While these have not yet been studied in depth, it convincingly shows an improvement in local sensitivity in images obtained with an internal electrode in comparison to a standard reconstruction method.