Development of interstitial antennas for hyperthermic treatment of cancer

我们研制了一种用于肿瘤间质热疗的微波同轴环槽式敷贴器。该辐射器是由0.86 mm外径同轴电缆制成的同轴缝隙天线，用于400-430 MHz微波频率。几个将微波能量辐射到周围组织的环形槽在外部导体上沿该电缆等距离放置，并且同轴电缆的尖端短路以扩大施加器尖端周围的加热区。天线可以插入到21G塑料导管中，通过调整缝隙的参数可以改变SAR沿导管的分布。电缆外导体上短距离设置多个同轴槽。每个天线被加载到一根细塑料导管中，然后将一组天线插入肿瘤中。在肌肉等效的琼脂体模中，研究了该敷贴器的热分布特性。该涂布器的优点是沿涂布器轴线的加热面积相对较大，加热面积相对均匀。这些优势已经在使用肌肉和植入的肿瘤的动物实验中得到了展示。组织病理学检查显示肿瘤大量凝固性坏死，有效地加热了肿瘤。该敷贴器与430 MHz微波热疗系统配合使用，从而使配备该系统的测温和温度控制系统也适用于间质热疗。

We have developed a microwave coaxial ring-slot applicator for interstitial hyperthermia in cancer therapy. The applicator is co-axial slots antennas made of a 0.86 mm outer diameter coaxial cable, and is used at a frequency of 400-430 MHz microwave. Several ring slots, which radiate microwave power into the surrounding tissue, are placed at equidistant intervals along this cable on the outer conductors, and the tip of the coaxial cable is short-circuited to expand the heating area around the tip of the applicator. The antennas can be inserted into a 21 G plastic catheter and the SAR distribution along them can be changed by ajusting the parameters of the slots. Multiple coaxial slots are arranged at short intervals on the outer conductor of the cable. Each antenna is loaded into a thin plastic catheter and an array of the antennas is then inserted into a tumor.The heating distributions characteristics of this applicator were investigated in the muscle-equivalent agar phantoms. The advantages of this applicator demonstrated were the relatively large haeting area and the relatively uniform heating area along the axis of the applicator. These advantages have been shown in animal experiments using the muscle and the implanted tumor. Histopathological examinations revealed massive coagulation necrosis of the tumors which were effectively heated with this applicater.The applicator was designed to be used with a 430 MHz microwave hyperthermia system, so that the temperature measurement and temperature control system equipped with the system are also availabel for the interstitial hyperthermia.