磁感应热治疗中磁介质的作用与影响因素

Effect of magnetic mediums in magnetic induction hyperthermia and influential factors

磁感应热疗作为一种新兴的加温治疗技术,是通过各种方法使磁介质靶向导入到机体组织中,在外部交变磁场的作用下局部升温加热,达到直接杀伤细胞或诱导细胞凋亡的作用。文章通过磁介质这一关键技术环节,探讨磁感应治疗中磁介质的作用与影响因素。首先,根据其物理尺寸的不同级数分别探讨了毫米级磁介质、微米级磁介质、纳米级磁介质的热效应和影响因素,其中毫米级磁介质多用于加温深部组织,其材料和体内排列分布对于磁感应治疗的效果影响较大;微米级磁介质多用于动脉栓塞热疗;纳米级磁介质在交变磁场中热效应的强弱对热疗效果影响显著,主要受颗粒浓度、粒径和表面处理等因素影响。同时,磁介质的居里点现象能实现治疗时的自控温,其进入组织的方式也会影响热疗的体内靶向性,另外,提高磁介质的组织相容性能够保证磁感应治疗的临床安全性。

Magnetic induction hyperthermia, as a new heating technology in the treatment of malignant tumors, is to transfer the magnetic mediums into the target tumor tissues through various procedures. Magnetic mediums produce heat to kill tumor cells directly or induce tumor cell apoptosis under the extracorporeal alternating magnetic field. This paper discussed the influence of magnetic mediums, the key link in this technology, upon the effect of tumor hyperthermia. According to their physical size of different levels, respectively, we discussed the thermal effects and influential factors of mm-scale magnetic medium, micron-scale magnetic medium, and nano-scale magnetic medium. Mm-scale magnetic medium is used for heating deep tumors, and its materials and the distribution in vivo have great influence on magnetic induction of tumor therapy. Micron-scale magnetic medium is commonly used for arterial embolism hyperthermia. The thermal effect of nano-scale magnetic medium in alternative magnetic field has a significant effect on hyperthermia, mainly due to particle concentration, particle size and surface treatment and other factors. In addition, the curie point phenomenon of magnetic medium achieves self-regulating temperature in treatment, and the pattern of magnetic medium into tissues will also affect the hyperthermia targeting in vivo. To improve the histocompatibility of magnetic medium can ensure the clinical safety of the magnetic induction hyperthermia in tumor therapy.