Design On Magnetic Fluid Hyperthermia Instrument With Temperature Feedback Control

Accurate temperature measurement and control is an urgent problem to be solved in magnetic fluid hyperthermia.In this thesis, magnetic nanothermometry is used for the tumor local temperature detection and a magnetic fluid hyperthermia instrument with temperature feedback control has been designed, which provides a new solution for the tumor local temperature measuring and control. The main contents are as follows.Firstly,based on the analysis of the magnetic materials loss mechanism, conclude that nanoparticle thermal effect depend on it dimension. Ferroferric oxide nanoparticles are essential component of the magnetic fluid, which diameter is10 nm, therefore the relaxation is the main mechanism of heat. The model of fluid temperature is established by referring to the research results of relaxation loss and verified by the magnetic fluid heating experiments. Research on MNPs thermal effect provides theory basis for dissipation analysis, which is helpful to understand temperature variation of magnetic fluid, as well as design magnetic fluid hyperthermia instrument and choose magnetic fluid.Secondly, study the principle of magnetic nanothermometry in triangular-wave magnetic field in order to precise temperature measurements, and propose reconstruct method to achieve MNPs magnetization which is the critical information of temperature inversion. Based on magnetization fourier analysis of MNPs magnetization, reconstruct expression of magnetization and achieve MNPs magnetization by harmonic measurement. Numerical simulations verify the principle and feasibility of this method, and the accuracy increases 50 times. On this basis, further research on the influence factors of temperature accuracy, such as magnetization, size distribution and number of harmonic, realize the optimization of magnetic nanothermometry in triangular-wave magnetic field.Finally, design magnetic fluid hyperthermia instrument with temperature feedback control, it use magnetic nanothermometry in triangular-wave magnetic field for temperature sensing, and change the temperature of the magnetic fluid by controlling heat. The experimental results show that the magnetic fluid hyperthermia instrument can control the temperature in 315±1.5K, and meet the requirements of tumor hyperthermia.