Development of coaxial-slot antenna for interstitial microwave hyperthermia

间质微波热疗用同轴缝隙天线的研制

• 批准号: 06452446
• 负责人: KASAI Haruo
• 金额: $ 0.77万
• 依托单位: Chiba University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06452446/
• 关键词: Interstitial hyperthermia; Coaxial-slot antenna; SAR distribution; Muscle-equivalent Phantom; Temperature distribution; Parasitic elements; Coaxial dipole applicator; Multiple coaxial ring slot; 加温性能評価指標; マイクロ波; カテーテル; 磁性体装荷; ファントム

・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.

·我们提出了用寄生单元代替同轴缝隙天线阵列的一些单元，以控制SAR（比吸收率）分布的形状。同轴偶极辐射器在其结构中，单环槽的两侧都有套管。这些套管可有效限制天线远端区域的电场。·用矩量法推导了同轴缝隙天线的电流分布。这种技术考虑了曾经被忽略的天线元件之间的电介质覆盖和相互作用。·发展了微波天线近区电场的数值模拟技术，并首次对SAR的特性进行了描述。在天线阵中，分析了SAR分布与阵元排列、馈电功率和馈电相位的关系。阐明了热斑在体表附近出现的机理。用本实验室研制的肌肉等效标准体模进行的实验结果与上述模拟结果一致。该体模已被日本热肿瘤学会QA委员会认定为微波热疗的标准。·在评价热疗器的加热性能时，通常采用归一化SAR分布[%]作为指标，这不适用于微波天线。我们已经提出了在热疗治疗开始后10分钟的43摄氏度的面积作为考虑耐热性的加热特性评价的指标。如果确定了血流速度，则已确认SAR值[W/kg]与治疗温度之间存在明确的对应关系。温度分布已用有限差分法计算。·针对具有多个环形缝隙的多同轴缝隙天线，提出了利用矩量法和传输线理论进行电流仿真的方法。

项目成果

Katsumi Furuya: "Development of new Muscle-equivalent phantom for microwave hyperthermia" 1995 Asia-Pacific Microwave Conference (Korea, Kaist). 2. 786-789 (1995)

Katsumi Furuya：“用于微波热疗的新型肌肉等效体模的开发”1995 年亚太微波会议（韩国，Kaist）。

呉孟憲: "複数のスロットを有する組織内加温用同軸スロットアンテナの基本解析" 電子情報通信学会技術報告. June. 1-6 (1995)

吴孟贤：“多槽组织加热同轴槽天线的基本分析”IEICE 技术报告 1-6（1995 年）。

古屋克己: "SAR推定に用いる新しい筋肉等価ファントムの開発" 電子情報通信学会技術報告. Jan.35-42 (1995)

Katsumi Furuya：“开发用于 SAR 估计的新肌肉等效模型”IEICE 技术报告。1995 年 1 月 35 日至 42 日。

呉孟憲: "マイクロ波組織内加温用同軸スロットアンテナの基本特性" 日本ハイパサーミア学会第11回大会. Sep.(1994)

吴孟宪：“微波组织加热用同轴缝隙天线的基本特性”，日本热疗学会第11届年会（1994年）。

古屋克己: "マイクロハイパーサーミアに用いる新しい筋肉等価ファントムの電気的特性" 電子情報通信学会1994年秋季大会. 244-244 (1994)

Katsumi Furuya：“用于微高温的新型肌肉等效体模的电气特性”IEICE 1994 年秋季会议 244-244 (1994)。