A Study of Super-selective Hyperthermia Using Dextran Magnetite Particles

热疗是临床上治疗癌症的第五种方法。但是，选择性地加热癌细胞是很困难的。在对深部肿瘤进行加热时，很难识别受热区域，而忽略了对正常组织的损伤。在之前的研究中，我们报道了使用葡聚糖磁铁矿颗粒（DM）和感应加热方法进行选择性热疗。在本研究中，对加热装置的转换和一些临床使用的研究进行了调查（如下）。1)加大了加热机组的功率，用于临床。该系统已设置为由计算机自动调节温度。2)用VX-2肿瘤建立新西兰大白兔深部肿瘤（如肝脏、结肠、膀胱肿瘤）。采用DM颗粒和感应加热装置对肿瘤进行加热。加热方法有瘤内注射法、球囊法和腔内法。对肝脏和膀胱肿瘤的增殖抑制进行了研究。3)联合抗癌药物（MMC）加热BALB/c小鼠甲基苯丙胺肿瘤。热疗组和mmc组治疗后寿命明显延长。4)设计了一种新的管状植入物加热深部肿瘤的方法。植入物为聚酯管，填充DM水溶胶，在感应场中测量植入物的模体温度。通过改变功率、植入物数量和排列方式，加热20 × 20 mm的区域。利用500千赫的感应加热和DM颗粒对癌症进行选择性加热。预计有可能应用于多种癌症的治疗。

Hyperthermia is using clinically as the 5th treatment for cancer. But, it is difficult to heat cancer cells selectively. When heating deep seated tumors, it is difficult to identify the heated area and ignore damage for normal tissues. In previous study, we have reported selective hyperthermia using dextran magnetite particles (DM) and inductive heating method. In this study, a conversion of heating unit and some studies were investigated for clinical use (as follows).1) The power of heating unit has been increased to use clinically. The system has been set up to regulate automatically the temperature by a computer.2) The deep seated tumors of New Zealand white rabbits were established with VX-2 tumors (ex. liver, colon, and urinary bladder tumor). These tumors were heated by DM particles and inductive heating unit. The methods of heating were intratumorous injection method, balloon method, and intracavitary method. The inhibition of tumor proliferation was investigated in liver and urinary bladder tumor.3) Meth-A tumors of BALB/c mice were heated by combination with anticancer drug (MMC). The increased life span after treatment were observed in the group of hyperthermia and MMC.4) A new heating method with tubular implants were designed to heat deep seated tumor. The implants were polyester tube and filled up with DM aqueous sol. The temperature of an phantom with implants was measured in the inductive field. An area of 20 x 20 mm was heated with changing of power, number of implants, and arrangement.The selective heating of cancer was expected with use of the inductive heating at 500 kHx and DM particles. The possibility is expected of an application for the treatment of various cancer.