Conditioning electrical impedance mammography system

Zarafshani, Ali, Bach, Thomas, Chatwin, Chris R, Tang, Shanshan, Xiang, Liangzhong and Zheng, Bin (2017) Conditioning electrical impedance mammography system. Measurement, 116. pp. 38-48. ISSN 0263-2241

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Abstract

A multi-frequency Electrical Impedance Mammography (EIM) system has been developed to evaluate the conductivity and permittivity spectrums of breast tissues, which aims to improve early detection of breast cancer as a non-invasive, relatively low cost and label-free screening (or pre-screening) method. Multi-frequency EIM systems typically employ current excitations and measure differential potentials from the subject under test. Both the output impedance and system performance (SNR and accuracy) depend on the total output resistance, stray and output capacitances, capacitance at the electrode level, crosstalk at the chip and PCB levels. This makes the system design highly complex due to the impact of the unwanted capacitive effects, which substantially reduce the output impedance of stable current sources and bandwidth of the data that can be acquired. To overcome these difficulties, we present new methods to design a high performance, wide bandwidth EIM system using novel second generation current conveyor operational amplifiers based on a gyrator (OCCII-GIC) combination with different current excitation systems to cancel unwanted capacitive effects from the whole system. We reconstructed tomography images using a planar E-phantom consisting of an RSC circuit model, which represents the resistance of extra-cellular (R), intra-cellular (S) and membrane capacitance (C) of the breast tissues to validate the performance of the system. The experimental results demonstrated that an EIM system with the new design achieved a high output impedance of 10MΩ at 1MHz to at least 3MΩ at 3MHz frequency, with an average SNR and modelling accuracy of over 80dB and 99%, respectively.

Item Type: Article
Keywords: Biomedical imaging equipment and instrument, screening and prescreening modality, breast cancer detection, electrical impedance tomography, bio-impedance current source, electrical impedance mammography, EIM, EIT
Schools and Departments: School of Engineering and Informatics > Engineering and Design
Research Centres and Groups: Industrial Informatics and Signal Processing Research Group
Subjects: R Medicine > R Medicine (General) > R856 Biomedical engineering. Electronics. Instrumentation
T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK0452 Electric apparatus and materials. Electric circuits. Electric networks
T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK7800 Electronics
Depositing User: Chris Chatwin
Date Deposited: 31 Oct 2017 09:30
Last Modified: 01 Dec 2017 14:48
URI: http://sro.sussex.ac.uk/id/eprint/70788

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