Design And Research Of Magnetic Induction Tomography Data Acquisition System

In recent years,Magnetic Induction Tomography(MIT),as an important branch of Electrical Impedance Tomography(EIT),has achieved rapid development.The MIT technology is based on the principle of eddy current detection,which reconstructs the conductivity distribution inside the imaging body by detecting changes in the magnetic field around the imaging body.This imaging method has the characteristics of noninvasive,non-contact,strong magnetic field penetration,etc.Compared with technologies such as MRI and CT,it also has the advantages of low cost and flexible detection methods.The early application of MIT technology in industrial testing,and gradually developed into the field of biomedicine,will have great prospects for future clinical applications.The MIT acquisition system is a prerequisite for the entire imaging.This article focuses on the research and design of the system.First,the COMSOL finite element analysis software was used for simulation analysis.The simulation results were consistent with the theory,which proved the effectiveness of the simulation.Then the model parameters were determined,which provided a theoretical basis and reference basis for the system construction.The design of the MIT system is divided into excitation module,detection module,scanning module,etc.In addition,it is necessary to analyze and design the magnetic field coil,power supply,and main control circuit.By analyzing and designing each module,the MIT acquisition system is completed.For this system,the purpose of designing the scanning platform is to increase the detection information while avoiding the influence of mutual inductance between the multi-array detection coils,making high-resolution image reconstruction possible.For the design of the coil,the specific parameters of the coil are finally determined by analyzing the influence of its resonance frequency and impedance on the detection signal.After the system was set up,the system was tested for sensitivity using an aluminum block,and the results proved that the sensitivity of the system to the position of the imaging body was 0.5 cm and the signal-to-noise ratio of the system was 79 d B.In order to explore the feasibility of the system for respiratory monitoring,a simulation experiment of respiratory monitoring was designed and conducted.The results show that the periodic changes of the detection results are consistent with the cycle of the respiratory process and have good synchronization,thus proving that the system can be used for real-time breathing Monitoring provides a new detection method for respiratory monitoring.Finally,a MIT reconstruction experiment was performed.The position and shape of the reconstructed imaging body were consistent with the real situation,which verified the effectiveness of the system for conductivity reconstruction.At the end of this paper,the improved way of multi-frequency excitation plus software phase detection is also prospected,which can obtain more abundant measurement information.The MIT data acquisition system designed in this paper can achieve 500 KHz,200 m A excitation,it can measure the phase difference of the induced magnetic field of0.01 °,and increases the amount of information of the detection magnetic field through the acquisition method of the scanning platform,which provides a valuable opportunity for MIT research.This kind of reliable phantom experiment platform can provide support for the research of imaging algorithms.