| Magnetic fluid hyperthermia is a kind of hyperthermia technique in which biocompatible magnetic nanofluids are injected into the targeted tumor tissue,and the magnetic fluid injection area is heated by applying an alternating magnetic field to kill the tumor tissue.Due to the precise targeting,high heating efficiency,non-toxicity and other advantages of magnetic fluid hyperthermia,it has great potential in the field of tumor treatment.However,because it is difficult to accurately control the temperature distribution of the target tissue,it is easy to cause unsatisfactory treatment effects or large damage to normal tissues,and it has not been widely used in clinical treatment.Therefore,this article aims to analyze the temperature field distribution in the tissue through numerical simulation methods,and quantitatively study the relationship between the heat generation power of the magnetic fluid and the injection volume with the tumor boundary reaching the treatment temperature of 42℃,so as to provides a theoretical reference for the temperature field control in the actual application process.A simplified three-dimensional biological tissue model is established by the finite element software COMSOL Multiphysics,and the heat generation power of the magnetic fluid is combined with the biological heat transfer model to solve the problem,and the temperature field distribution in the tissue during the hyperthermia is obtained.The Arrhenius model is used to analyze the thermal damage of the tissue,and the effects of different magnetic fluid parameters,magnetic field parameters,injection volume,and number of multi-point injections on the tissue temperature and damage effect are explored.The results show that:with the equal increase of different magnetic fluid and magnetic field parameters,the temperature rise rate in the tissue is also different.Among them,the volume fraction increases by the same amount as the temperature rise.The greater the field strength,the faster the temperature rise,and the higher the frequency,the slower the temperature rise.When the volume of injection is constant,multi-point injection can increase the uniformity of temperature distribution,but the treatment score will decrease.The magnetic field and temperature field distribution of the solenoid coil and the Helmholtz coil magnetic field generator are analyzed by numerical methods,and the temperature difference of the tissue at different positions of the magnetic field during multi-point injection is explored,and proposed non-iso-dose injection to improve the uniformity of the temperature field distribution.Research shows that:the two kinds of magnetic field generating devices have good magnetic field uniformity in the biological tissue area.When the strength of the central magnetic field is the same,the temperature field distribution of the two is the same,but the solenoid coil will produce a larger thermal damage area in the normal tissue.With the offset of the tissue from the center of the magnetic field,the temperature difference can reach 1℃ when the offset distance is 10mm.Non-equal dose multi-point injection can reduce the maximum temperature in the tissue,so that more tumor tissues are in a reasonable treatment temperature range.When the injection ratio k is 1-1.5,the volume fraction is more affected.The experimental device was designed to conduct a magnetic fluid experiment.The experimental results show the influence of the magnetic field strength and volume fraction on the heating effect of the magnetic fluid,which is consistent with the theoretical analysis results.Comparing the experimental results with the simulation results,the temperature rises trends of the two are basically the same,which verifies the validity of the numerical analysis. |
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