Based On The Breast Of The Rotating Electrode Method For Electrical Impedance Tomography

Electrical Impedance Tomography (ETT) is a new type of medical imaging technique. In EIT, the approximation for the spatial distribution of impedance (or conductivity) within the object can be reconstructed via an array of electrodes is attached around the object. The history of EIT is more than ten years and about thirty research groups engage the investigation of EIT at present. The advantages are that the technique is inexpensive, portable, and safe. It has the potential for widespread use in medicine for continuous monitoring at the bedside, in the intensive care unit, or in remote medical facilities. In medicine, its accuracy has been demonstrated in imaging lung, heart, stomach and brain hematoma. Moreover, the technique can be used not only in imaging anatomical structures, but also in imaging functional structures. This is most helpful for preventing and diagnosing disease, prior to disease happened.The principal potential applications of EIT lie in biomedical imaging, whose biological basis is to acquire the information of physiology and pathology, via injecting electrical current on the periphery of cross section of a human body. The impedance of biological tissue represents some information from function or disease of organs. Depending on the electrical impedance property of tissue, EIT can provide a kind of non-invasive tomography.The measurement of mamma based on EIT is called mammary EIT. The mammary EIT uses electrodes in measuring the voltage or the electricity of the mamma, and based on these measurements, the distribution of impedance within the object can be reconstructed in one dimension or two dimensions or three dimensions. The theory basic of mammary EIT is that the distribution of electric field in homogeneous medium changes when there is a different conductivity in the medium. The healthy mamma is mainly consisted by fat, it can be considered as a homogeneous medium. The conductivity of the cancer is higher than the fat. In a mammary electric field, the cancer can be considered as a lower resistance or higher conductivity. It can change the distribution of the electricity in the mamma. If put a measuring electrode on the surface of the mamma, the trait of the structure between the electrodes can be reflected by the electricity in the measuring electrode.The article brings forward a new algorithm of imaging reconstructed based on Ohmic Law. The data collected system uses rotating electrodes according to the algorithm. The main contents of the article are as follows:1,Bring forward a algorithm of imaging reconstructed based on Ohmic LawThe technique of EIT is a contrary problem of electric current calculation, The core of the EIT is the algorithm of imaging reconstructed, but the result of the algorithm is not good as consummating the theory is hard. The algorithm brought by this article is that: Put a drive voltage around the measured object; Measure the electricity within the measured object; Calculate the impedance of the measured object based on Ohmic Law.2,Design a data collected system by using rotating electrodesThe number of electrodes in EIT is finite as it is limited by the algorithm and the amount of the information collected from the measured object is fewer. The data collected system put forward by this study can measure the object from different orientation by rotating the electrodes. The type of the data collecting is flexible and the information is large.3,Reconstruct the imaging of the simulative impedanceReconstruct the imaging of the simulative impedance according to the answer of the algorithm. The analysis of the imaging indicates that this method is practicable. But the differentiation is low, the algorithm needs to be amended.4,Analyze the distribution of the electric field in the homogeneous medium when it imports inhomogeneous mediumThe core of the algorithm's amendment is the modification of the equation that is established in homogeneous medium. The modification of the equation is amending it to approach to inhomogeneous medium. We analyze the distribution of the electric field in the homogeneous medium when it imports inhomogeneous medium that provides a reference for the algorithm's amendment.