Location of carcinoma emulators in experimental breast models using electrical impedance tomography based on linear back projection

Introduction : The electrical impedance measurement and characterization of biological tissues allow to distinguish between a healthy and pathological tissues. The use of techniques such as electrical impedance tomography is widely used in clinical testing through various applications. In this work the Linear Back Projection (LBP) method is employed to reconstruct images from electrical impedance measurements in order to obtain the location of carcinoma emulator previously inserted within female-breast-shaped agar-agar models. Method : A ring arrangement of eight electrodes was used for measuring the impedance on the seven female-breast-shaped agar-agar models. A cross section of a healthy female breast (without emulators) corresponding to the measurement plane of the ring electrode arrangement was designed and simulated in the COMSOL software. The sensitivity maps of each pair of electrodes along the impedance measurement were computed using the conductivity distribution data obtained from the simulated model. Finally, the reconstruction of the electrical tomography images was achieved by applying the LBP algorithm to the electrical impedance values measured form the electrode ring arrangement. Results : The sensitivity maps were computed from the electrical impedance measurements for each defined experimental model. As a result, a sensitivity matrix characterizing the electrical potentials distribution within the simulated measurement plane in COMSOL was obtained. The zone locations for all the experimental models with carcinomas emulators inserted outside the center of the electrodes ring arrangement were correctly obtained. Discussion or Conclusion : According to the results obtained from the described project, the proposed methodology allows the generation of images to locate carcinoma emulators with approximate diameters of 1 cm through a non-iterative approach. Therefore, the location does not require a high computational complexity. The localization of a carcinoma emulator inserted on the central zone of the female breast model was not correctly obtained due to the low sensitivity of the electrode ring arrangement in such zone.