Development of Heat Generating Magnetic Materials for Hyperthermia and Application to Medical Treatment

研制了用于癌组织热疗的植入材料，并进行了临床研究。主要研究成果如下：1.用于热疗的Fe-Pt合金植入材料的耐腐蚀性大于不锈钢，其具有低居里点和通过涡电流损耗产生的大的热。然而，当植入物嵌入兔子的大腿组织中时，在X射线分析中检测到少量溶解的Fe元素（1.0 x 10^<-4>g/cm ^2月）。为了防止合金元素的溶解，用硅烷和磷酸在种植体表面涂覆生物相容性复合SiO_2。涂层显著提高了涂层的耐蚀性.制备了Fe-Pt合金粉末样品作为发热材料，通过磁滞损耗法测试了其磁性能。粉末材料的发热量足以用于热疗。提出了一种喷雾干燥法对粉体颗粒进行SiO_2包覆.研究了CaO-MgO-Fe_2O_3系陶瓷材料作为一种新型的热疗粉末植入材料。结果表明，（MgO）_<1-x>（Fe_2O_3）_x的x=0.525和（CaFe_4O_7）_<1-y>（MgFe_2O_4）_y的y=1.0的材料具有较大的滞后发热量，其滞后发热量是Fe_3O_4的数倍。材料的居里点低于Fe_3O_4.5。本文报道了几例应用铁铂合金种植体治疗脑肿瘤和舌肿瘤的临床试验。热疗效果显著，脑肿瘤为45.5%，舌肿瘤为100%。

The implant materials for hyperthermia of cancer tissues were developed and the clinical investigations were performed. Results of the research are summarized as follows :1. The corrosion resistance of the Fe-Pt alloy implant material for hyperthermia, which has low Curie point and large heat generation through the eddy current loss, is larger than that of a stainless steel. However, when the implant was embedded in the tissue of the thigh of a rabbit, the dissolved Fe element was a little bit detected in the X-ray analysis(1.0 x 10^<-4> g/cm^2 month).2. In order to prevent the alloy elements from dissolving, the biocompatible compound SiO_2 was coated on the implant using silane and phosphorus acid. The coating improved the corrosion resistance remarkably.3. The powder samples of Fe-Pt alloys were prepared as a heat generation materials through magnetic hysteresis loss. The heat generation of the powder material was enough to be used for hyperthermia. A spray-drying method was developed for the SiO_2 coating of the powder particles.4. The ceramic materials of CaO-MgO-Fe_2O_3 system whose elements are all biocompatible were investigated as new powder implant materials for hyperthermia. It was found that the materials of x=0.525 for (MgO)_<1-x>(Fe_2O_3)_x and y=1.0 for (CaFe_4O_7)_<1-y>(MgFe_2O_4)_y have the large heat generation through hysteresis loss which is several times larger than that of Fe_3O_4. The curie points of the materials are lower than that of Fe_3O_4.5. The clinical treatment for brain tumors and tongue tumors were tried for several cases using Fe-Pt alloy implants. The effects of hyperthermia were remarkable, 45.5% for brain tumors and 100% for tongue tumors.