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

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

The electric properties of human tissue can potentially be used as an additional diagnostic parameter, e.g., in tumor diagnosis. In the framework of radiofrequency safety, the electric conductivity of tissue is needed to correctly estimate the local specific absorption rate distribution during MR measurements. In this study, a recently developed approach, called electric properties tomography (EPT) is adapted for and applied to in vivo imaging. It derives the patient's electric conductivity and permittivity from the spatial sensitivity distributions of the applied radiofrequency coils. In contrast to other methods to measure the patient's electric properties, EPT does not apply externally mounted electrodes, currents, or radiofrequency probes, which enhances the practicability of the approach. This work shows that conductivity distributions can be reconstructed from phase images and permittivity distributions can be reconstructed from magnitude images of the radiofrequency transmit field. Corresponding numerical simulations using finite-difference time-domain methods support the feasibility of this phase-based conductivity imaging and magnitude-based permittivity imaging. Using this approximation, three-dimensional in vivo conductivity and permittivity maps of the human brain are obtained in 5 and 13 min, respectively, which can be considered a step toward clinical feasibility for EPT. Magn Reson Med, 2011. © 2011 Wiley-Liss, Inc.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/mrm.22832

Quantitative conductivity and permittivity imaging of the human brain using electric properties tomography.

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.

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

A Mazaletskaya

Papers

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

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