Bone cancer is rare in adults, the most affected persons by this disease are young people and children. The common treatments for bone cancer are surgery, chemotherapy, and targeted therapies; however, all of them have side-effects that decrease the patient’s quality of life. Thermotherapy is one of the most promising treatments for bone cancer; its main goal is to increase the tumor temperature to kill cancerous cells. Although some micro-coaxial antennas have been used to treat bone tumors, most of them are designed to treat soft tissue. Therefore, the purpose of this work is to analyze the thermal behavior of four micro-coaxial antennas specifically designed to generate thermal ablation in bone tissue to treat bone tumors, at 2.45 GHz. The proposed antennas were the metal-tip monopole (MTM), the choked metal-tip monopole (CMTM), the double slot (DS) and the choked double slot (CDS). The design and optimization of the antennas by using the Finite Element Method (FEM) allow to predict the optimal antenna dimensions and their performance when they are in contact with the affected biological tissues (bone, muscle, and fat). In the FEM model, a maximum power transmission was selected as the main parameter to choose the optimum antenna design, i.e., a Standing Wave Ratio (SWR) value around 1.2–1.5. The four optimized antennas were constructed and experimentally evaluated. The evaluation was carried out in multilayer phantoms (fat, muscle, cortical, and cancellous bone) and ex vivo porcine tissue at different insertion depths of the antennas. To fully evaluate the antennas performance, the standing wave ratio (SWR), power loss, temperature profiles, and thermal distributions were analyzed. In the experimentation, the four antennas were able to reach ablation temperatures (>60 °C) and the highest reached SWR was 1.7; the MTM (power loss around 16%) and the CDS (power loss around 6.4%) antennas presented the lowest SWR values depending on the antenna insertion depth, either in multilayer tissue phantom or in ex vivo tissue. These proposed antennas allow to obtain ablation temperatures with an input power of 5 W after 5 min of treatment; these values are lower than the ones reported in the literature.

中文翻译：

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用于治疗骨肿瘤的微同轴天线组的热评估：多层体模和离体猪组织中的设计、参数化 FEM 建模和评估

骨癌在成年人中很少见，受这种疾病影响最大的人是年轻人和儿童。骨癌常见的治疗方法有手术、化疗和靶向治疗；然而，它们都有降低患者生活质量的副作用。热疗是治疗骨癌最有希望的疗法之一。其主要目标是提高肿瘤温度以杀死癌细胞。虽然一些微同轴天线已被用于治疗骨肿瘤，但其中大部分是设计用于治疗软组织的。因此，这项工作的目的是分析专门设计用于在 2.45 GHz 下在骨组织中产生热消融以治疗骨肿瘤的四个微型同轴天线的热行为。提议的天线是金属尖端单极子 (MTM)、扼流金属尖端单极子 (CMTM)、双槽 (DS) 和扼流双槽 (CDS)。使用有限元方法 (FEM) 设计和优化天线可以预测天线与受影响的生物组织（骨骼、肌肉和脂肪）接触时的最佳天线尺寸及其性能。在 FEM 模型中，选择最大功率传输作为主要参数来选择最佳天线设计，即驻波比 (SWR) 值约为 1.2-1.5。构建并实验评估了四个优化的天线。评估是在多层体模（脂肪、肌肉、皮质和松质骨）和 使用有限元方法 (FEM) 设计和优化天线可以预测天线与受影响的生物组织（骨骼、肌肉和脂肪）接触时的最佳天线尺寸及其性能。在 FEM 模型中，选择最大功率传输作为主要参数来选择最佳天线设计，即驻波比 (SWR) 值约为 1.2-1.5。构建并实验评估了四个优化的天线。评估是在多层体模（脂肪、肌肉、皮质和松质骨）和 使用有限元方法 (FEM) 设计和优化天线可以预测天线与受影响的生物组织（骨骼、肌肉和脂肪）接触时的最佳天线尺寸及其性能。在 FEM 模型中，选择最大功率传输作为主要参数来选择最佳天线设计，即驻波比 (SWR) 值约为 1.2-1.5。构建并实验评估了四个优化的天线。评估是在多层体模（脂肪、肌肉、皮质和松质骨）和 构建并实验评估了四个优化的天线。评估是在多层体模（脂肪、肌肉、皮质和松质骨）和 构建并实验评估了四个优化的天线。评估是在多层体模（脂肪、肌肉、皮质和松质骨）和天线不同插入深度的离体猪组织。为了全面评估天线性能，分析了驻波比 (SWR)、功率损耗、温度分布和热分布。在实验中，四个天线都能够达到烧蚀温度（>60°C），最高达到的 SWR 为 1.7；MTM（功率损耗约 16%）和 CDS（功率损耗约 6.4%）天线呈现最低 SWR 值，具体取决于天线插入深度，无论是在多层组织模型中还是在离体组织中。这些提议的天线允许在治疗 5 分钟后以 5 W 的输入功率获得消融温度；这些值低于文献中报道的值。