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磁共振热疗(magnetic resonance hyperthermia)是近年来新兴的一种纳米医学治疗方法,由磁共振的硬件架构产生特定交变磁场,有效地加热磁性纳米粒子,以直接或间接地杀死癌细胞,体现诊疗一体化.提高磁性纳米粒子的加热效率是当前磁共振热疗领域亟待解决的难题之一.磁性纳米粒子的加热效率不仅与粒子本身的大小、性质以及尺寸分布有关,还和聚集状态有关.该研究利用3D Metropolis蒙特卡罗模拟方法,模拟了不同温度下磁性纳米粒子的磁共振热动力学行为及其团聚与分离现象;并通过修正过的郎之万方程,建立了相变临界温度与外加磁场频率的函数关系.模拟结果显示,磁性纳米粒子悬浮液中多聚体的相对含量随着温度的升高而降低,达到临界温度后,多聚体完全分离成单体;而提高交变磁场频率可以显著降低临界温度,且存在临界频率,高于此临界频率后临界温度不再受外加磁场频率影响,达到稳定.因而在临界频率下预热磁性纳米粒子悬浮液,使得多聚体分离成单体,可优化磁性纳米粒子的热疗效率.
Magnetic resonance hyperthermia is a new type of nanomedicine treatment method in recent years. The magnetic resonance magnetic structure generates a specific alternating magnetic field, which effectively heats magnetic nanoparticles to directly or indirectly kill cancer cells. Reflect the integration of diagnosis and treatment.Improving the heating efficiency of magnetic nanoparticles is one of the most urgent problems to be solved in the field of magnetic resonance hyperthermia.The heating efficiency of magnetic nanoparticles is not only related to the size and properties of the particles themselves and the size distribution but also to the aggregation state In this study, the 3D Metropolis Monte Carlo simulation method was used to simulate the magnetic resonance thermodynamics behavior of magnetic nanoparticles at different temperatures and their agglomeration and separation phenomena. Based on the modified Langzomon equation, the phase transition critical temperature And the frequency of the applied magnetic field.The simulation results show that the relative content of multimers in the magnetic nanoparticle suspension decreases with the increase of the temperature and the polymer is completely separated into monomers after the critical temperature is reached, Variable magnetic field frequency can significantly reduce the critical temperature, and there is a critical frequency above which the critical temperature is no longer affected The influence of the applied magnetic field frequency is reached, and thus the suspension of the magnetic nanoparticles is preheated at the critical frequency so that the polymer is separated into monomers to optimize the thermotherapy efficiency of the magnetic nano-particles.