Theoretical And Experimental Study On Magnetic Fluid Hyperthermia In The Treatment Of Tumors

Magnetic fluid hyperthermia(MFH)is a type of the hyperthermia used in the treatment of tumors.Compared with other hyperthermia methods,MFH has obvious advantages,namely its targeted nature and absence of toxicity or side effects.Thus it has become a popular research topic in the field of tumor treatment in China and abroad.At present,the studies of MFH tend to focus on material preparation and experiments,but lack effective theoretical support.Guided by the principle that magnetic fluids produce heat in the alternating magnetic field,this dissertation conducts relevant studies on temperature rise in human tissues during the process of hyperthermia,to provide a theoretical basis for the application of MFH.First,research into the principle of superparamagnetic magnetic fluid nanoparticles producing heat in the alternating magnetic field is carried out,and the heating power of magnetic fluids is deduced according to Neel and Brownian relaxation magnetic loss mechanisms.Comparative analysis on heating power is made among different cases by changing the parameters of magnetic fluids and alternating magnetic fields.Analysis of results shows that the heating power is affected by a variety of factors,including magnetic field frequency,magnetic field intensity,particle diameter,and volume fraction.Second,after analysis on the heat transfer modes in human tissues,the mathematical model of heat transfer model in human tissues is established on the basis of the Pennes bioheat transfer equation.The temperature distribution of tissues is calculated in a two-dimensional space through the finite element method,and the tissues' temperature distribution during the process of hyperthermia is simulated through the COMSOL software.The influencing factors of tissues' temperature distribution are compared and analyzed,in order to support that the multi-point injection method can significantly improve the effect of hyperthermia.Next,the alternating magnetic field generating device is designed according to the magnetic circuit theory.The simulation results confirm that the magnetic field distribution is even and can be used for MFH.The coupled model of the magnetic field and temperature field is established,and it is used to analyze the effects of magnetic field frequency,magnetic field intensity,human tissue parameters and blood perfusion rate on MFH,in order to ensure the optimal parameters are obtained.Finally,the designed MFH experimental device is used to conduct test tube and in vitro tissue experiments.The results of test tube experiments show that the heat production of magnetic fluids is affected by magnetic field frequency and intensity,which is consistent with the theoretical analysis.The rules of temperature rise in tissues are obtained through the in vitro tissue experiments,which conform to the simulation analysis,confirming the validity of simulation and the feasibility of experiments.