Development of coaxial-slot antenna for interstitial microwave hyperthermia

我们已提议替换同轴槽天线阵列中的一些元素，以控制合成孔径雷达（特定吸收率）分布的形状。Coaxial-dipole应用程序在其结构中的两侧都有睡眠。这些睡眠在限制电磁场到天线的离散区域上是有效的。同轴槽天线的当前分布是通过使用即时方法产生的。这项技术需要一个远距离覆盖物的帐户和天线之间的相互天线元素，因为它曾经是消极的。数值模拟技术用于近电场微波天线已经开发出来，我们已指定了第一次合成孔径雷达的行为。在天线阵列中，合成孔径雷达分布对元素的排列、喂养功率和喂养阶段的依赖性，以满足每个元素都是显而易见的。“热点出现的机制接近身体表面已经被清晰化了。”实验结果与Muscle-equivalent标准幻影开发，并与我们的实验室达成一致，与上述模拟结果。这一幽灵已经被确认为日本超热肿瘤学协会QA委员会的微波超热症标准。由于对超热应用者的加热性能的评估，正常化的合成孔径雷达分布[%]已使用到目前为止的指数，因此微波天线是不合适的。我们在10分钟后提出了一个43-centigrade的区域，即热治疗的开始，这是一个关于热特性的指数，以评估热耐受性的指标。在合成孔径雷达值[W/kg]和治疗温度之间不可mistakable correspondence，如果血液流动率已被确认。温度分布已经用精细差异法计算了。对于多同轴槽天线，因为天线比一个环槽多，所以使用瞬时方法和传输线理论进行了当前模拟。

・We have proposed to replace some elements of the coaxial-slot antenna array with parasitic elements to control the shape of SAR (Specific Absorption Rate) distributions. Coaxial-dipole applicator has sleeves on both sides of the single ring slot in its structure. Those sleeves are effective in restricting electrical field to distal area of the antennas.・The current distribution of coaxial-slot antenna has been derive by using moment method. This technique takes account of a dielectric cover and mutual between antenna elements that had ever been neglected.・Numerical simulation technique for near electric field of interstitial microwave antennas has been developed, and we have specified the behavior of SAR for the first time. In antenna array, dependencies of SAR distributions on arrangement of elements, feeding power and feeding phase for each element have been explicated. The mechanism of hot spot appearance nearby body surface has been clarified.・Experimental results with muscle-equivalent standard phantom developed in our laboratory have agreed with the above simulated results. This phantom has been recognized as the standard for microwave hyperthermia by the QA Committee in the Japanese Society of Hyperthermic Oncology.・For evaluation of the heating performance of hyperthermia applicators, the normalized SAR distribution [%] has been used as an index so far, which is unsuitable for microwave antenna. We have proposed the area of 43-centigrade at 10 minutes after the start of hyperthermia treatment as an index of heating characteristics evaluation considering the heat tolerance. Unmistakable correspondence between SAR value [W/kg] and therapeutic temperature has been confirmed if blood flow rate is identified. Temperature distributions have been calculated with finite-difference method.・For multiple coaxial-slot antenna that has more than one ring slot, current simulation by using moment method and transmission line theory has been proposed.