A study of frequency inductive heating using liposomal

日本的热疗目前以射频波的电容式加热为主，但选择性加热较为困难，对于位于腹腔深部的胃肠道肿瘤的热疗仍有研究空间。本研究将平均粒径为15 nm的Fe_3O_4颗粒包裹在脂质体的脂质分子膜上，并加入偶联卟啉，制备了脂质体铁磁颗粒（以下简称HP-LM），目的是建立一种深部肿瘤的选择性加热方法。在兔下肢植入VX-2肿瘤细胞，动脉内给予HP-LM，高频感应加热。与非给药组相比，动脉内给药组显示出肿瘤温度的显著升高以及肿瘤生长抑制作用。然而，重复给药HP-LM被认为是必要的，以防止肿瘤长时间的生长。因此，通过从动脉内注射储存库中反复给药HP-LM进行高频感应加热，非给药和不加热组21天后肿瘤生长4.2倍，重复给药和加热组21天后肿瘤生长1.7倍。对肿瘤进行组织学检查时，发现肿瘤组织中有磁性颗粒堆积。然而。网状内皮螺旋器官的积累量也很高，因此对代谢途径的研究是未来研究的主题。

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.