| Magnetic induction hyperthermia is an important branch of many tumor hyperthermia methods.It has prominent features,obvious advantages,and rapid development.It is very likely as a priority choice for the treatment of tumors.Therefore,it has high academic value and research significance.At present stage,the main research of magnetic induction hyperthermia stays in the preparation of magnetic nanomaterials and its experimental aspects,but few researches on magnetic induction hyperthermia devices are performed.In order to overcome the disadvantages of uneven distribution of the magnetic field direction and intensity of the coil-type magnetic field generating device for animal magnetic induction hyperthermia,this thesis optimizes the coil and compares results of the optimized coil and the original coil.It provides a theoretical basis for the application of magnetic induction hyperthermia.Firstly,the electromagnetic foundation of magnetic induction hyperthermia was analyzed.The heating mechanism and the choice of working frequency and field strength parameters of magnetic induction hyperthermia were introduced.The magnetic field distributions of the circular coil,solenoid coil,and hollow cylinder coil were calculated,and the changes of the coils were compared when the magnetic induction intensity of the same magnitude was generated.The cylinder coil with outer diameter was chosen as the main magnetic field generating device for magnetic induction thermotherapy.Finally the AC/DC module of the finite element software was introduced.Secondly,the optimization of the uniformity of magnetic induction hyperthermia field was introduced.The coil parameters and calculation methods were determined according to the size of the magnetic induction.The correctness and feasibility of the software calculation were verified by comparison with the calculated values of the coils provided in the literature and the simulation results of the software.Aiming at the disadvantages of uneven distribution of the magnetic field direction and intensity of the coil type magnetic field generating device,the original coil was optimized by adding a compensation coil at both ends of the coil.When the current changed,the magnetic induction intensity B of the compensation coil moving from both ends to the middle was calculated with compensation coil the number of turns remained unchanged.When the compensation coil's current remain unchanged the magnetic induction intensity B of the compensation coil moving from both ends to the middle was calculated with the number of turns changed.The rate of change of the magnetic induction at different positions in the same area,then determined the optimal position of the compensating coil.In the best position,the influence of the incoming compensation coil current and the number of turns on the magnetic induction B was discussed,and the parameters of the compensation coil were determined.Comparing the magnetic induction intensity of the compensation coil and the non-compensation coil,the magnetic induction strength of the coil has been increased by about 4.2% compared with that of the solenoid coil without the compensation coil under the same conditions.The magnetic induction intensity at the center of the compensation coil reached 11.3 m T,and the magnetic field uniformity increased by about 66.7%.Finally,the realization of the small magnetic induction hyperthermia hardware circuit was analyzed.The design and implementation of magnetic induction thermotherapy control circuit were introduced.The control circuit was used to verify the designed coil.The data for comparison was given from the magnetic induction intensity of the coil center,the magnetic induction intensity along the coil axis direction and the uniformity of the coil magnetic induction intensity.The results were compared with the theoretical values,and it was basically consistent with the simulation results,so that the effectiveness of the simulation and the feasibility of the experiment was confirmed. |
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