Assesment and optimisation techniques for an electrical impedance mammography system

Lingham, Benjamin (2014) Assesment and optimisation techniques for an electrical impedance mammography system. Masters thesis (MPhil), University of Sussex.

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Abstract

Breast cancer detection through the use of Electrical Impedance Tomography (EIT) has been proposed for a number of years. Typically in an EIT or when in use in breast cancer detection, Electrical Impedance Mammography (EIM) system, the patient interface is that of electrodes. Positive and negative sinusoidal signals are injected into a patient multiple times at multiple frequencies, recording the developed surface voltages that naturally develop from the impedance of the body. A 2D or 3D reconstruction and visualisation of the impedance distribution is possible through the use of the recorded voltage amplitude and phase. Higher resolution images are achieved through higher electrode density (i.e.smaller electrode distance). Furthermore, tissue has a characteristic frequency response,which can be recorded if different injection frequencies are utilised. The higher thefrequency, the deeper the signal can penetrate into tissue and deeper through the cellular structures, potentially leading to tissue characterisation through its frequency response.

Our group has suggested a unique combined EIT and ultrasound multimodal imaging system to detect breast cancer. This will use an EIT system to initially scan the breast,combining this parametric data with the high-resolution images of ultrasound to give a more accurate diagnosis. The prototype, known as V2, was functional but performed poorly, especially with respect to the signal to noise ratio. Images generated with this system were unclear. My role within the group was to analyze the performance of the V2 system and research best practice methods to improve the existing design, taking into consideration the intricacies of EIT hardware design and the targeted application. The improvements I suggested were incorporated into the V3 system, which was then compared with the V2 system, and showed significant performance improvement.

Item Type: Thesis (Masters)
Schools and Departments: School of Engineering and Informatics > Engineering and Design
Subjects: R Medicine > RC Internal medicine > RC0071 Examination. Diagnosis Including radiography > RC0078 Radiography. General works > RC0078.7.E45 Electrical impedence tomography
Depositing User: Library Cataloguing
Date Deposited: 07 Jul 2014 10:27
Last Modified: 08 Oct 2015 09:47
URI: http://sro.sussex.ac.uk/id/eprint/49007

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