[Material design and temperature field simulation analysis of tumor radiofrequency ablation needle].

To solve the problems of small one-time ablation range and easy charring of the tissue around the electrode associated with the tumor radiofrequency ablation needle, based on the multiphysical field coupling analysis software COMSOL, the effects of needle material, the number of sub needles and the bending angle of sub needles on the ablation effect of radiofrequency ablation electrode needle were studied. The results show that compared with titanium alloy and stainless steel, nickel titanium alloy has better radiofrequency energy transmission efficiency and it is the best material for electrode needle. The number of sub needles has a great influence on the average necrosis depth and the maximum necrosis diameter. Under the same conditions, the more the number of sub needles, the larger the volume of coagulation necrosis area. The bending angle of the needle has a great effect on the maximum diameter of the coagulated necrotic area, but has little effect on the average necrotic depth. Under the same other conditions, the coagulation necrosis area formed by ablation increased with the increase of the bending angle of the sub needle. For the three needles with bending angles of 60 °, 90 ° and 120 ° analyzed in this paper, the one with bending angle of 120 ° can obtain the largest coagulation necrosis area. In general, the design of nickel titanium alloy with 120 ° bending 8-pin is the optimal. The average depth of radiofrequency ablation necrosis area is 32.40 mm, and the maximum necrosis diameter is 52.65 mm. The above optimized design parameters can provide guidance for the structure and material design of tumor radiofrequency ablation needle.为解决肿瘤射频消融针一次性消融范围小以及电极周围组织易发生烧焦炭化的问题，本文基于多物理场耦合分析软件COMSOL，研究针体材料、子针个数和子针弯曲角度对射频消融电极针消融效果的影响规律。研究结果表明，相较于钛合金和不锈钢，镍钛合金具有更好的射频能量传导效率，是电极针的最佳制作材料；子针个数对平均坏死深度和最大坏死直径均有较大影响，相同条件下，子针个数越多，凝固坏死区域体积越大；子针的弯曲角度对凝固坏死区域的最大直径影响较大，对平均坏死深度的影响较小。在其它条件均相同的情况下，消融形成的凝固坏死区域随子针弯曲角度的增加而增大。对于本文分析的60 °、90 °和120 °三种子针弯曲角度而言，120 °的弯曲角度可获得最大的凝固坏死区域。综合而言，镍钛合金120 °弯曲8子针的设计最优，射频消融坏死区域的平均深度为32.40 mm，最大坏死直径为52.65 mm。上述优化设计参数可为肿瘤射频消融针的结构与材料设计提供指导。.