Temperature Rise Characteristics Of Magnetic/Laser Hyperthermia Based On Fe₃O₄ Magnetic Nanoparticles

How to effectively treat malignant tumor has always been one of the focuses and hotspots of scholars all over the world.Magnetic fluid hyperthermia（MFH）technology and photothermal therapy（PTT）technology based on the idea of hyperthermia have been widely concerned in the field of tumor treatment due to their unique advantages.In recent years,studies have shown that some magnetic nanoparticles have good magnetothermal and photothermal conversion capabilities,which are suitable for both MFH and PTT.Therefore,MFH combined with PTT based on magnetic nanoparticles has emerged as the times require.However,the existing research on MFH combined with PTT is mainly experimental,and the research on numerical simulation is still relatively scarce.On this basis,the temperature rise characteristics of magnetic/optical hyperthermia process based on Fe₃O₄ magnetic nanoparticles were studied theoretically.The optical properties of spherical,rod-shaped and core-shell Fe₃O₄ nanoparticles in a certain wavelength range were calculated by using the finite element simulation software COMSOL multiphysics.It was found that the absorption factors of spherical and rod-shaped Fe₃O₄ nanoparticles decreased first and then increased between 700 nm and 1000 nm,while the change trend of absorption factors of core-shell nanoparticles was different.Based on the limited heat transmission speed of biological tissue,a skin tumor heat transfer model based on heat wave model was established,and the distribution of thermal damage in biological tissue was calculated by Arrhenius equation.The effects of different factors on the temperature field and thermal damage distribution of biological tissue under the action of alternating magnetic field or laser were numerically investigated.The influence of laser power and magnetic fluid concentration on the temperature rise curve of magnetic fluid was studied.The effects of MFH single-mode,PTT single-mode and MFH combined with PTT dual-mode were compared.It was found that when the alternating magnetic field was combined with laser,the superposition effect of the two heat sources made the temperature rise effect of biological tissue better,and the smaller parameters can be used to achieve better thermotherapy effect than the alternating magnetic field or laser alone.On this basis,the influences of different factors on the temperature field and thermal damage distribution of biological tissue under dual-mode hyperthermia were explored.The temperature field distribution of tumor with large blood vessels treated by magnetic fluid hyperthermia is studied.The effects of the radius of large blood vessels,the velocity of blood flow,the position of blood vessels and the number of blood vessels on the temperature distribution of biological tissues were analyzed,which provided guidance for the practical application of magnetic fluid hyperthermia.