Research On Electrical Conductivity Characteristics Of The Lung Applied To ET Imaging

Lung cancer occurs in the bronchial epithelium,and the incidence of lung cancer has increased significantly in the past 50 years.In western industrialized countries and some large industrial city in China,the incidence of lung cancer in male malignant tumor has been ranked first in female incidence rate also increased rapidly,the incidence of lung cancer in men has been the first place,it is also increasing rapidly among women,accounting for second or third of the most common malignant tumors in women.Lung cancer has become one of the major diseases endangering peoples’ life and health.Currently,medical imaging techniques that have been used in clinical diagnosis include computed tomography(CT)scanning,magnetic resonance imaging(MRI)and the like.CT scan has the characteristics of fast imaging,clear image and so on and it has been widely used in clinical diagnosis.Because of its high safety and no damage,electrical tomography(ET)technology is expected to be an effective method for clinical diagnosis.Combining CT images to study the electrical conductivity of human lung tissue can provide a priori information for ET imaging.The main contents of this thesis are as follows:1.We obtained data of 81 patients with lung cancer who had electrical conductivity information in General Hospital Affiliated to Tianjin Medical University during the past 2014-2015 years,and recorded the air pollutants content of 15 observe stations which is posted by Tianjin environmental monitoring center.Then,we used MySQL database and front and back technology to build data query screening spa applications,which can be more convenient and fast for data storage,query and modification.2.We introduced the principle of human lung composition and electrical characteristics,and analyzed the existing data,established the analysis model by MATLAB and studied the distribution of pulmonary conductivity parameters.According to the CT diagram,the case data is divided into two parts,in the parts with CT graph,assign the target pixels in the model according to the measured conductivity.The distribution of partial electrical conductivity in the absence of CT is treated by the attenuation of the central lobe of the cancerous tissue shown in the case.In the MATLAB simulation,the interpolation method is used to roughly describe the impedance distribution of the human lung.And we used volume rendering method to reconstruct 3D lung model.3.The new optimization methods we proposed are mainly aimed at the Tikhonov and FCM-EIT regularization algorithms.In the improved algorithm,the utilization rate of the boundary measurement voltage is improved,and the electrical conductivity information of the existing biological tissue is considered as a prior value.The imaging accuracy of the algorithms and its’ application potential in the field of visualization are all improved.