Research Of In Vivo Ablation Catheter Based On Electrical Impedance Tomography

Due to the advantages of low cost,non-invasive and non-radiation operation,Electrical Impedance Tomography(EIT)has been widely used in medical fields such as cardiopulmonary function monitoring,breast cancer detection and brain activity imaging.Considering the fact that human tissues and metal catheters have significant differences in electrical conductivity,we use EIT to carry out imaging simulation research on catheters during microwave ablation surgery of liver.If we can further accurately corresponds imaging figures to the three-dimensional image of the organ before the operation,and display the catheter as a real-time virtual probe,then we may achieve real-time navigation of the ablation operation.1)First,on the theoretical basis of electrical impedance imaging technology,three reconstruction algorithms,namely equipotential lines back-projection method,NewtonRaphson method and BP neural network learning method,are respectively used to simulate the electrical impedance imaging of the metal catheter in the cylinder,thus the correctness of the above three algorithms is verified.The simulation results show that the inverse projection method is fast,but the resolution quality is not high.The calculation time of Newton-Raphson method is long,and the accuracy problem also exists.BP learning method has high imaging accuracy,but it needs a large number of experimental data as training samples.2)Then we simulated the temperature distribution during microwave ablation of liver.Furthermore,Mimics and Comsol were used to establish the human liver model.Taking liver ablation surgery as an example,the simulation research of electrical impedance imaging technology was carried out using back-projection and BP neural network learning method.The simulation results show that EIT can not only display the contour of liver organs in vivo,but also show the location of ablation catheter.3)Finally,we presents the design of electrical impedance imaging system.This scheme adopts modular design,including signal source,multiplex switch and electrode,data processing and ARM processor,etc.,which provides a foundation for the establishment of hardware platform to verify the accuracy of the model and the correctness of the algorithm.