Research Of Electromagnetic Tracking Experimental System For Medical Application

Electromagnetic Tracking is a technique that takes magnetic positioning as the core, combined with signal detection and processing, computer science and applied mathematics etc. In recent years it has been widely used in many fields especially the medical application.This paper proposes a numerical arithmetic for solving the magnetic field nonlinear equations, based on in-depth research of the method for 3-D position measurement using orthogonal dipoles field. The simulation results with typical parameter have proved that the Inverse-Broyden method can acquire the real-time solution of the magnetic equations efficiently. The effective application area is also discussed grounded on numerical algorithms. In view of the limits of the practical machining, the eccentric and deflection-angle errors model is made, as well as the error recognition and correction. The simulation and analysis indicate that the positioning errors can be decreased effectively by means of the method discussed above. The theoretical analysis and simulation results have provided a basis for magnetic field positioning in practice.According to the practical requirements, the magnetic position tracking system hardware is developed. In the transmitting part, the design of the orthogonal transmitting coils and its driving and controlling circuit is able to transmit the time-division orthogonal magnetic with sufficient power accurately. In the receiving part, the filtering, amplifying and collecting of the magnetic signal are realized by the probe designed with MR sensor.In the design of the program, non-linear equations solving algorithm, nonlinear/linear error correction algorithm and time-division magnetic signal processing algorithm are made as the core algorithms of the application to achieve the transformation of the magnetic signal to 3-D coordinates. OpenGL is also applied to accomplish the vivid display of the positioning process.Finally, through the evaluation of the whole magnetic position tracking system, certain positioning parameters are acquired and the comparison of the positioning accuracy between different application areas is also made. Besides that, the factors which affect the positioning accuracy are analyzed concretely. In the end of the paper, the practical application and further development of the medical electromagnetic tracking system are generally described.