A study of frequency inductive heating using liposomal

日本的热疗目前以射频电容加热为主，但选择性加热困难，腹腔深部胃肠道癌的热疗仍有研究空间。本研究将平均粒径为15 nm的Fe_3O_4微粒与脂质体的脂质分子膜包裹，制备了含有血卟啉的脂质体铁磁微粒（HP-LM），旨在发展一种深部肿瘤的选择性加热方法。将VX-2肿瘤细胞移植于兔下肢，动脉内注射HP-LM，高频感应加热。动脉内给药组与非给药组相比，显示出肿瘤温度显著升高以及肿瘤生长抑制作用。然而，HP-LM的重复给药被认为是必要的，以防止肿瘤生长的一段较长的时间。因此，采用高频感应加热，从储药器中重复注射HP-LM，21天后，不给药不加热组肿瘤生长4.2倍，重复给药加热组肿瘤生长1.7倍。当肿瘤组织学检查时，磁性颗粒在肿瘤组织中积聚。然而.在网状内皮螺旋器官中的累积也很高，因此对代谢途径的研究是今后研究的主题。

As for hyperthermia in Japan, cases of capasitive heating using RF wave presently account for the majority, but selective heating is difficukt and there still is a room for study as to hyperthremia for gastrointestinal cancers which are located deep in the abdominal cavity. In the present study we prepared liposomal ferromagnetic particles (hereinafter refered to as HP-LM) by cvering Fe_3O_4 particles of which mean particle size is 15 nm with lipid molecular membrane of liposome and having hem atoporphyrin, the purpose of developing a selective heating method for deep tumors. Furthermore, VX-2 tumor cells were implantd in the lower legs of rabbit, and HP-LM was administered intraarterialy, andhigh frequency inductive heating was done. The intraarterial administration group, as compared with the nonadministration group, showed a significant rise in temperature in tumors as wellas the tumor-growth-inhibiting effects. However, repeated administration of HP-LM was considered necessary toprevent the growth of tumorsfor a long period of time. Therefore, high frequency inductive heatingwas done by administrating HP-LM repeatedlyfrom a reservoir for intraarerial injection, with the tumor grown 4.2 times after 21 days in the nonadiministration and nonheating group, and 1.7 tines after 21 days in the repeated administration and heating group. When the tumor was ecamined histologically, magnetic particles were accumulated in the tumor tissue. However. accumulation in the reticuloendot helial organs was also high, so a study on the metabolic route is the subject of future study.