Simulation And Optimization Of Key Components In Magnetic Nanoparticles Tumor Hyperthermia Technology

Real-time and accurate temperature information is a critical parameter in tumor hyperthermia,which directly affects the efficacy of tumor hyperthermia.Due to the characteristics of real-time and non-invasive,magnetic nanoparticles thermometer(MNPT)are expected to accurately acquire internal temperature information of living bodies and opaque objects and have great potential for tumor hyperthermia applications.However,the current measurement accuracy of MNPT is low,which seriously hinders its popularization and application in tumor hyperthermia.This thesis takes the critical core devices in the magnetic nanoparticles tumor hyperthermia as the starting point.The magnetic field excitation and detection devices are optimized,respectively,to reduce the temperature measurement error of MNPT.The main contents are as follows:(1)The dependence among the position error of the air-core coil,the strength of the excitation magnetic field,and the temperature error in the magnetic field excitation device are studied.The theoretical model of position error is constructed.The method of using a compensation coil to reduce the error of magnetic induction intensity is proposed,thereby decreasing the temperature measurement error of MNPT.At the same time,it was found that in the process of constructing a magnetic field excitation device composed of multiple sets of air-core coils,there is a minimum error transmission route,which provides a theoretical basis for the precise assembly of critical components.(2)Aiming at the problem that the critical components(Helmholtz coil)in the magnetic field excitation device generate heat and cause fluctuations in the magnetic field,resulting in significant errors in temperature measurement.Study the complex multi-physics coupling relationship in the Helmholtz coil,and build a mathematical model among the magnetic field,temperature field,and thermal stress field.The applicable conditions under the conditions of adiabatic,natural heat dissipation,and forced air cooling were studied respectively,and it was found that the influence trend of temperature changes under different conditions on the coil material parameters and the method of forced air cooling can effectively reduce the temperature measurement error of MNPT.(3)Aiming at the irreconcilable contradiction between the aperture size of the detection coil and the signal-to-noise ratio in the magnetic-weakening measurement device,an open detection coil structure design is initially carried out.The optimization research of double-coil structures such as cylindrical,flat-cylindrical,U-shaped,and racetrack-shaped is carried out,respectively.By adjusting the angle between the double coils,the uniform magnetic field area is taken as the critical design parameter.Analyzing and studying the uniform magnetic field areas on both sides of the dual coils A/B of different structural types,it is found that when the dual coils constructed with the double racetrack structure have an included angle of 30°,the area of the uniform magnetic field generated in the A side area is better,that is 9.2mm~2.