A new applicator of RF capacitive heating for head and neck cancer

我们设计了一种新型的敷贴器(U形敷贴器)，将直径15厘米的平板电极弯曲成U形。采用U型敷贴器和平板敷贴器对日本热疗学会QA模体进行加热。用涂有聚四氟乙烯的热电偶测量体模内的温度，用热像仪测量加热后的垂直截面温度分布。U形喷头减小了不良边缘效应，获得了良好的热分布。在加热后的热分布上，平面敷贴器将体模的最高温区移至体模的较浅侧，U形敷贴器将最高温区移至体模的核心附近。热分布的变化不仅与边缘效应的减小有关，还与电极间距的变化有关。在我们的一位下咽癌同事的临床应用中，U形敷贴器比平面敷贴器减少了疼痛和其他并发症，口底和食道入口处的最高温度高出近2ﾟC。温度的变化可能是由于边缘效应减小，电极间距缩短，电极与皮肤距离不均匀的改善，U型敷贴器有望在临床热疗肿瘤学中发挥重要作用。

We devised a new type of applicator (U-shape applicator), with bending the flat electrode of 15 cm in diameter into U-shape. Japan hyperthermia society QA phantoms were heated with the U-shape applicator and with the flat applicator. The temperature in the phantom was measured with the Teflon coated thermocouples and the vertical sectional thermal distributions after heating were taken with a thermography unit. The untoward edge effect was reduced and favorable thermal distribution was obtained with the U-shape applicator. On the thermal profile after heating, the highest temperature zone was shifted to the shallower sides of the phantom with the flat applicator, and was near the core with the U-shape applicator. The change of the thermal distribution may be not only due to the decrease of the edge effects but the changes of the distance between both electrodes. In the clinical application to one of our co-workers who was suffering hypopharyngeal cancer, pain and other complication were reduced and the maximum temperature of the oral floor and at esophageal inlet was nearly 2ﾟC higher with the U-shape applicator than with the flat applicator. The change of the temperatures may be due to the decrease of the edge effects, the shortening of the distance between both electrodes, and improvement of non-uniform distance from electrodes to skin.U-shape applicator can be expected to play an important role in clinical hyperthermic oncology.