Electrical conductivity imaging via contactless measurements

Gençer, N.G.; Tek, Mustafa

doi:10.1109/42.790461

Cited by 68 publications

(57 citation statements)

References 36 publications

(61 reference statements)

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“…When taking measurements, the magnetic signals are picked first to judge the position and state of the illness, and then electrical signals are picked to get encryption measurement and imaging. This well supports the follow-up algorithm and image reconstruction and overcomes the model error produced by individual differences and the different medical treatments [8,9].…”

Section: System Featuresmentioning

confidence: 88%

Biological impedance cross evaluation and imaging from composite measurements of magnetic and electrical methods

Peng

Xiao²,

He³

et al. 2015

BME

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Abstract. Because of the need for rapid detection and location of diseases in clinical applications, this work proposes a composite measurement of magnetic induction tomography (MIT) and electrical impedance tomography (EIT). This paper is composed of the following aspects: portable and integral hardware design, stable dual constant-current sources, the composite detection method, cross-plane data acquirement, 3-dimensional image reconstruction and so on. A qualitative evaluation of conductivity, resolution and relative position error were taken by combining the EIT and MIT methods via the experiment model. The sensitivities of both methods were analyzed to improve the imaging results. The reconstruction results reveal that the system is capable of obtaining better physiological measurements, which is very useful in clinical monitoring, quick medical diagnosing and preliminary screening of community health.

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Section: System Featuresmentioning

confidence: 88%

Biological impedance cross evaluation and imaging from composite measurements of magnetic and electrical methods

Peng

Xiao²,

He³

et al. 2015

BME

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“…The electrical eddy currents induced in the conducting body therefore also time-harmonic and generated secondary electromagnetic fields that can be measured directly by electrodes (Gencer et al, 1994) or by a separate induction coil (Gencer, 1999). In conjunction with the usual EIT method, the MIT method has the potential to greatly improve the resolution of electrical anomalies within the body since the orientation and location of the transmitting antenna is not constrained to the surface of the skin, but rather, can be located almost arbitrarily above the body and therefore subject the body to a greater variety of EM excitation modes.…”

Section: Geophysical Imaging Methodsmentioning

confidence: 99%

Linking the Geosciences to Emerging Bio-Engineering Technologies

Cygan¹,

Ho²,

Weiss³

2002

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Is application of Geosciences research at Sandia National Laboratories to biological and human health systems beneficial to the lab's biotechnology efforts? This LDRD project was funded to answer that question for three application areas: biochemistry, bioengineering, and human health. The biochemistry section includes modeling for protein folding and improved drug delivery substrates. For those molecular simulations, a hybrid energy forcefield was developed to model the conformation of an oligopeptide within the clay interlayer. Results demonstrate that the nonbonded interactions are especially important in understanding the control of the structure and function of proteins as modified by inorganic substrates, and that the protein structure may be denatured by the clay surface. More sophisticated molecular simulations involving waters of solvation for the protein, hydrated clay interlayers, and different charged distributions in the clay substrates are recommended for future research. The bioengineering section focuses on drug delivery and hazardous chemical absorption through the skin. Percutaneous absorption of chemicals was developed using a probabilistic, multiphase, heterogeneous model of the skin. Penetration routes through the skin included intercellular diffusion through the stratum corneum, diffusion through aqueous-phase sweat ducts, and diffusion through oil-phase hair follicles. Mass fluxes were calculated for varying lengths of time, and sensitivity analyses showed that the aqueous solubility limit, thickness of the stratum corneum, and aqueous molecular diffusion coefficient were important input parameters. Complex flow and transport models used for enhanced oil recovery, geothermal energy production, and subsurface contaminant migration could be used to further model percutaneous absorption. The human health section includes a review of the geophysical imaging methods that have been used for imaging the interior of the human body, including electrical impedance tomography and magnetic induction tomography.Accurate 3D interpretations of surface or near surface voltage/current or electromagnetic field measurements are dependent upon the inversion algorithms used. EIT impedance inversion is computationally less challenging than EM induction inversion, but rapid and resource-efficient solutions are being developed for geophysical applications. Details of this report can be found at

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“…Edge FEM has been employed for the medical and industrial MIT forward problem [20], [30]. Solving the forward problem of MIT using a scalar field has been reported by [9]. An eddy current formulation of A r , A r − V presented by [20] models the electric field in the conducting region as sum of the scalar field V and primary magnetic vector potential, and a reduced magnetic vector potential A r .…”

Section: Introductionmentioning

confidence: 99%

Absolute Conductivity Reconstruction in Magnetic Induction Tomography Using a Nonlinear Method

Soleimani

Lionheart

2006

IEEE Trans. Med. Imaging

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Magnetic Induction Tomography attempts to image the electrical and magnetic characteristics of a target using impedance measurement data from pairs of excitation and detection coils. This inverse eddy current problem is nonlinear and also severely ill posed so regularization is required for a stable solution. A regularized Gauss-Newton algorithm has been implemented as a nonlinear, iterative inverse solver. In this algorithm one needs to solve the forward problem and recalculate the Jacobian matrix for each iteration. The forward problem has been solved using an edge based finite element method for magnetic vector potential A and electrical scalar potential V , a so called A, A-V formulation. A theoretical study of the general inverse eddy current problem and a derivation, paying special attention to the boundary conditions, of an adjoint field formula for the Jacobian is given. This efficient formula calculates the change in measured induced voltage due to a small perturbation of the conductivity in a region. This has the advantage that it involves only the inner product of the electric fields when two different coils are excited, and these are convenient computationally. This paper also shows that the sensitivity maps change significantly when the conductivity distribution changes, demonstrating the necessity for a nonlinear reconstruction algorithm. The performance of the inverse solver has been examined and results presented from simulated data with added noise.

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Electrical conductivity imaging via contactless measurements

Cited by 68 publications

References 36 publications

Biological impedance cross evaluation and imaging from composite measurements of magnetic and electrical methods

Biological impedance cross evaluation and imaging from composite measurements of magnetic and electrical methods

Linking the Geosciences to Emerging Bio-Engineering Technologies

Absolute Conductivity Reconstruction in Magnetic Induction Tomography Using a Nonlinear Method

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