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不可逆电穿孔作为一种新型微创肿瘤治疗方案,经过近10 a的发展已进入临床实验阶段。临床实验发现不可逆电穿孔肿瘤治疗效果在很大程度上取决于治疗计划是否完善。然而目前缺乏对于不可逆电穿孔临床治疗计划的优化,仅借助于简单的电场分布计算以及实验经验来确定方案。为解决这一问题,运用有限元分析软件COMSOL Multiphysics建立了不同尺寸的球形、椭球形肿瘤模型及其周边正常组织数值模型;基于遗传算法对电极布置以及脉冲参数进行了优化,实现肿瘤组织完全消融而正常组织损伤最小的优化目标。考虑到实际硬件条件以及安全情况,脉冲电压幅值不可能无限增大,所以限制脉冲电压幅值在3 000 V以内。当肿瘤体积较小时,2针足以完全消融肿瘤,但是随着肿瘤体积的增大,所需电压以及对正常组织的损伤也随之增大,2针下正常组织损伤体积与肿瘤体积之比最大达到0.986 2。随着肿瘤体积进一步增加,需要增加电极针数,此时完全消融肿瘤所需电压有所降低,减少了对正常组织的损伤。借助遗传算法实现了对不同尺寸、不同形状肿瘤的完全消融,得出了最佳的电极布置以及脉冲参数的最优选择,为不可逆电穿孔临床应用推广奠定坚实的基础。
Irreversible electroporation as a new minimally invasive treatment of cancer, after nearly 10 a development has entered the clinical trial phase. Clinical trials found that irreversible electroporation tumor treatment depends largely on the treatment plan is perfect. However, currently, there is a lack of optimization of the clinical treatment plan for irreversible electroporation. Only the simple calculation of the electric field distribution and experimental experience are used to determine the solution. To solve this problem, spherical and ellipsoidal tumor models of different sizes and their surrounding normal tissue numerical models were established using the finite element analysis software COMSOL Multiphysics. The electrode arrangement and pulse parameters were optimized based on genetic algorithms to achieve complete ablation of tumor tissues The normal tissue damage the smallest optimization goal. Taking into account the actual hardware conditions and safety conditions, the pulse voltage amplitude can not be infinitely increased, so the limit pulse voltage amplitude within 3 000 V. When the tumor volume is small, the 2-pin is enough to completely ablate the tumor, but as the tumor volume increases, the required voltage and the damage to the normal tissue also increase, and the ratio of the damage volume to the tumor volume of the 2-pin normal tissue is the largest Reached 0.986 2. With the further increase of tumor volume, need to increase the number of electrodes, then the voltage required to completely ablate the tumor is reduced, reducing the damage to normal tissue. By means of genetic algorithm, the complete ablation of tumors of different sizes and shapes has been completed, and the optimal electrode arrangement and the optimal choice of pulse parameters have been obtained, laying a solid foundation for the clinical application and promotion of irreversible electroporation.