A 3D multi-frequency response electrical mesh phantom for validation of the planar structure EIT system performance

Zarafshani, Ali; Qureshi, Tabassum-Ur-Razaq; Bach, Thomas; Chatwin, Chris; Soleimani, Masoud

doi:10.1109/eit.2016.7535306

Cited by 9 publications

(9 citation statements)

References 23 publications

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“…The key factor or evaluation index in assessing performance and reliability of multi-frequency systems is signal-to-noise ratio (SNR) and its accuracy [36][37][38][39], which are directly affected by the output impedance of the current excitation system when measuring the voltage between two points of the sample tissue. In reality, the output impedance of the current source is not infinite.…”

Section: Current Excitation Systemmentioning

confidence: 99%

Conditioning Electrical Impedance Mammography System

et al. 2018

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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 at 1MHz to at least at 3MHz frequency, with an average SNR and modelling accuracy of over 80dB and 99%, respectively.

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Section: Current Excitation Systemmentioning

confidence: 99%

Conditioning Electrical Impedance Mammography System

et al. 2018

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“…Briefly, since a breast mostly consists of fat and fibro-glandular tissues, the breast density could be simulated by two types of agar conductive materials of "fat tissues" as background conductivity mixed with different ratios of "fibro-glandular tissues" as a breast phantom design. These are two types of agar conductive of 0.03 % and 0.185 % saline solution, which correspond to have the conductivity around and at 25°C [31,32]. In practice,…”

Section: Breast Phantommentioning

confidence: 99%

“…In this study we built nonbiological phantoms to simulate the biological medium for measuring dielectric impedance spectrum signals [31]. We made breast phantoms based on different tissue conductivities using different agar saline solutions.…”

Section: Breast Phantommentioning

confidence: 99%

Untitled

2017

JABB

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Breast density is a well-recognized important breast cancer risk factor. However, accurately assessing breast density is difficult. Although the mammographic density is the most popular method to assess breast density in current clinical practice, it is not accurate and reliable due to the overlap of breast tissues and inter-reader variability. In order to more accurately assess breast density, we proposed a new non-invasive assessment technology based on the measurement of dielectric impedance spectrums of the breast regions. The objective of this study is to test the feasibility of this new technology through a unique phantom study. The phantom design is based on mixing two types of agar saline materials with two different levels of electrical conductivity corresponding to fat and fibro-glandular tissue conductivities. In the phantom design considerations, we assembled four breast phantoms to mimic four breast density categories defined by the Breast Imaging Reporting and Data System. The testing results showed that as the increase of the simulated "fibro-glandular" tissues inside the phantom, the measured electrical impedance values monotonically decreased. The testing results were consistent and reproducible at different positions between detection probes and breast phantom surface when considering and calibrating the systematic errors. Thus, this study demonstrated the feasibility of developing and applying a new dielectric impedance measurement technology and device to assess breast density, which is low-cost, non-invasive, non-hazard and easy-to-use. If successful in future tests, this new method has potential to assist better assessing breast cancer risk for developing an optimal personalized breast cancer screening paradigm.

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“…It has been used as a medical imaging technique by producing conductivity or permittivity images [3][4][5]. Similarly, in the case of SHM, conductivity images are produced to distinguish the condition of a structure by assessing the location, size, strain, and severity of damage.…”

Section: Introductionmentioning

confidence: 99%