t. This paper surveys some of the work our group has done in electrical impedance tomography.

Electrical Impedance Tomography

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/j.molonc.2008.04.001

Imaging and cancer: A review

Electrical impedance tomography (EIT) is a relatively new imaging method that has evolved over the past 20 years. It has the potential to be of great value in clinical diagnosis; however, EIT is a technically difficult problem to solve in terms of developing hardware for data capture and the algorithms to reconstruct the images. This review looks at the development of EIT and how it has evolved. It focuses on its clinical applications, examining hardware for the collection of data and reconstruction algorithms to generate images. Finally, this review looks at future developments that are evolving from EIT. These new variations use mixed modalities that may produce interesting new clinical imaging tools.

https://www.annualreviews.org/doi/pdf/10.1146/annurev.bioeng.8.061505.095716

Bioimpedance tomography (electrical impedance tomography)

A review of electrical impedance techniques for breast cancer detection

The electric conductivity can potentially be used as an additional diagnostic parameter, e.g., in tumor diagnosis. Moreover, the electric conductivity, in connection with the electric field, can be used to estimate the local SAR distribution during MR measurements. In this study, a new approach, called electric properties tomography (EPT) is presented. It derives the patient's electric conductivity, along with the corresponding electric fields, from the spatial sensitivity distributions of the applied RF coils, which are measured via MRI. Corresponding numerical simulations and initial experiments on a standard clinical MRI system underline the principal feasibility of EPT to determine the electric conductivity and the local SAR. In contrast to previous methods to measure the patient's electric properties, EPT does not apply externally mounted electrodes, currents, or RF probes, thus enhancing the practicality of the approach. Furthermore, in contrast to previous methods, EPT circumvents the solution of an inverse problem, which might lead to significantly higher spatial image resolution.

Determination of Electric Conductivity and Local SAR Via B1 Mapping

A medical device which allows imaging of the distribution of conductivity in 3D in regions below the skin surface has been developed and tested Its purpose is to enable early detection and preliminary diagnosis of breast tumours Design of the measuring system and software are described Results of clinical evaluation of the system are presented EIT images of healthy and cancerous breasts are presented and discussed The system is able to visualize various states of the breast and it may be possible to apply it to breast cancer detection

https://www.mobecomm.com/docs/pubs/A_3D_electrical_impedance_tomography-(EIT)-system_for_breast_cancer_detection.pdf

A 3D electrical impedance tomography (EIT) system for breast cancer detection.

Results of development and testing of the new medical imaging system are described. The system uses a planar array consisting of 256 electrodes and enables obtaining images of the three-dimensional conductivity distribution in regions below the skin's surface up to several centimeters deep. The developed measuring system and image reconstruction algorithm can be used for breast tissue imaging and diagnostics, in particular for malignant tumor detection. Examples of tomographic images obtained in vivo during clinical tests are presented. The mammary gland, being an organ-target, alters at the background with such physiological events as menstrual cycle, pregnancy, lactation, and postmenopause. The objectives of this paper include estimation of the possibilities of electrical impedance mammography for investigation of mammary glands' state among women with different hormonal status. We found that electrical impedance mammograms from different groups had clear visual distinctions and statistically significant differences in mammary glands' conductivity. Our data on conductivity distribution in the mammary gland during different physiological periods will allow us to use it as normal values in the future, to continue this research on mammary glands with different pathology.

/pdf/three-dimensional-eit-imaging-of-breast-tissues-system-1ohrbutnbf.pdf

Three-dimensional EIT imaging of breast tissues: system design and clinical testing

The possibility of formation of a virtual guiding system from a bunch of plasma channels of the filaments of femtosecond laser pulses for transmission of microwave radiation in air is considered. The effective conductivity and the skin depth of the laser plasma of such filaments are calculated for the microwave band. Optimum spatial configurations of plasma channels corresponding to a single-wire transmission line and a hollow cylindrical waveguide are proposed. Estimates of the energy loss of microwave radiation in plasma waveguides of various configurations are obtained.

Plasma channels formed by a set of filaments as a guiding system for microwave radiation

The results of a preliminary clinical evaluation of a one-frequency electrical impedance tomography (EIT) system enabling static in vivo imaging are presented. The design of the measuring system and image reconstruction software are described. Thirty-one subjects were examined and divided into four clinical groups. The first group consisted of 22 patients with clinical diagnosis of lung cancer with tumour localization in one lung. The second group consisted of seven healthy subjects. A patient after a one-sided pneumectomy and another with one-sided emphysema diagnosis were also examined. Static EIT images of a healthy human chest and a chest with various abnormalities are given and discussed. The evaluated system distinguishably visualizes various states of lungs and thorax including lung cancer. The average static conductivity of an affected lung in the first clinical group statistically differs from the average conductivity of a healthy lung. In spite of low spatial resolution, according to preliminary results, the method can be sensitive to cancer and other lung diseases in screening investigations.

https://iopscience.iop.org/article/10.1088/0967-3334/23/1/304/pdf

Preliminary static EIT images of the thorax in health and disease.

For controllable generation of an isolated attosecond relativistic electron bunch [relativistic electron mirror (REM)] with nearly solid-state density, we proposed [V. V. Kulagin et al., Phys. Rev. Lett. 99, 124801 (2007)] to use a solid nanofilm illuminated normally by an ultraintense femtosecond laser pulse having a sharp rising edge (nonadiabatic laser pulse). In this paper, the REM characteristics are investigated in a regular way for a wide range of parameters. With the help of two-dimensional (2D) particle-in-cell (PIC) simulations, it is shown that, in spite of Coulomb forces, all of the electrons in the laser spot can be synchronously accelerated to ultrarelativistic velocities by the first half-cycle of the field, which has large enough amplitude. For the process of the REM generation, we also verify a self-consistent one-dimensional theory, which we developed earlier (cited above) and which takes into account Coulomb forces, radiation of the electrons, and laser amplitude depletion. This theory shows a good agreement with the results of the 2D PIC simulations. Finally, the scaling of the REM dynamical parameters with the field amplitude and the nanofilm thickness is analyzed.

V. N. Kornienko

Papers

A 3D electrical impedance tomography (EIT) system for breast cancer detection.

Three-dimensional EIT imaging of breast tissues: system design and clinical testing

Plasma channels formed by a set of filaments as a guiding system for microwave radiation

Preliminary static EIT images of the thorax in health and disease.

Characteristics of relativistic electron mirrors generated by an ultrashort nonadiabatic laser pulse from a nanofilm