Spectral Capacitively Coupled Electrical Resistivity Tomography for Breast Cancer Detection

Abstract

Early detection of breast cancer is key for a better survival rate, so there are huge demands for a safe and reliable breast cancer screening method, which currently is not available. Earlier studies are showing that the impedance spectroscopy can be an effective discriminator for breast tumor against healthy tissues. Traditional electrical impedance tomography (EIT) has progressed well into clinical stages for such an application with some promising results. But EIT generally operates at low frequencies, ranging typically lower than 1 MHz. Previous research work has suggested that the important information on the tumor impedance spectra exists in the higher frequency domain. Thus, this work focuses on the introduction and the evaluation of a spectral capacitively-coupled electrical resistivity tomography (CCERT) for breast cancer diagnosis. Compared to the traditional EIT, CCERT can reach a much higher frequency domain producing the spectroscopic images in a broader range. This in turns offers improved discrimination of tumors against normal tissues via frequency difference imaging or spectral imaging as it is shown in this paper. Additionally, direct contact between the EIT electrodes and the surface of the body, which causes significant challenges and uncertainties in measured data, is avoided in CCERT inherently a contactless method. In this paper, a 3D in-silico model of the CCERT system is created and solved using the finite element method (FEM) to simulate the forward model for each frequency. The feasibility simulation analysis is conducted based on the existing clinical breast cancer data and a CCERT reconstruction. For the experimental verification, an 8-electrode laboratory phantom was tested with the excitation frequency ranging from 200 kHz to 13 MHz. The simulation and experimental results show the promising potential of this method for breast cancer imaging. The wide-range spectroscopic images provide better discrimination of tumors against healthy tissues through their spectral conductivity profile as well as the rate of changes in spectral conductivity images. INDEX TERMS Breast cancer diagnosis, capacitively coupled electrical resistivity tomography (CCERT), conductivity spectrum of bio-samples, multi-frequency tomography.

Application of Deep Neural Network to the Reconstruction of Two-Phase Material Imaging by Capacitively Coupled Electrical Resistance Tomography

“…Based on the capacitively coupled contactless conductivity detection (C 4 D) technique, CCERT avoids contact error by inserting an insulation layer between the electrodes and conductive contents [11]. Besides that, experiments show that CCERT could have a larger excitation frequency domain than that of traditional ERT, which results in better imaging results [15,16]. Therefore, CCERT is attracting more and more researchers' attention.…”

“…Therefore, CCERT is attracting more and more researchers' attention. So far, CCERT has been applied in gas-liquid two-phase materials, brain imaging, and breast cancer detection [16][17][18].…”

Electrical Impedance Tomography: From the Traditional Design to the Novel Frontier of Wearables

“…Because many tumors are characterized by significantly different conductivity and permittivity from surrounding normal tissues, EIT might be able to identify them by exploiting these different electrical properties [ 92 , 93 , 94 ]. Indeed, an increasing number of studies are investigating the use of EIT for screening and early detection of cancer, with breast cancer being the main application in addition to skin, thyroid, liver, cervix and lung cancer [ 92 , 93 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 ]. In breast imaging, 3D maps of conductivity distributions have reported detectable breast cancer models sized about 12–14 mm [ 103 ], up to 5 mm with 4.9 mΩ sensitivity [ 104 ] with 3D systems of respectively 128 and 90 electrodes.…”

Linearization Point and Frequency Selection for Complex-Valued Electrical Capacitance Tomography

“…Electrical impedance tomography (EIT) is another imaging technique widely used in medical imaging that can obtain complex impedance information [6]. In [7][8][9], a capacitively coupled ERT (CCERT) is proposed and applied to image the conductivity distribution without contact with liquids, which can be regarded as the combination of ECT and ERT because it applied ECT sensors to collect resistance information. In [10,11], phase information of complex admittance is used to reconstruct electrical parameter distribution, such as loss factor or permittivity.…”