血流对HIFU肿瘤治疗影响的数值仿真研究

Simulation Study on Blood Flow Effect of Large Vessels in Tumor Tissue during High-Intensity Focused Ultrasound Therapy

在高强度聚焦超声治疗肿瘤问题的研究中,高强度聚焦超声(high-intensity focused ultrasound,HIFU)治疗大血管周边的肝肿瘤时,血流对HIFU形成可治疗焦域的影响难以预测和实时监控,可能导致肿瘤组织残留或者血管的损伤等临床治疗问题。为了预测大血管对HIFU肝肿瘤治疗的影响,以HIFU治疗血管周边肿瘤为例建立三维仿真模型,利用Westervelt声传播方程及Pennes生物热传导方程,用时域有限差分法数值仿真HIFU治疗形成的温度场。仿真结果表明,当大血管位于目标治疗区域附近时,血管位置对60℃以上可治疗焦域的形状、大小及位置均有显著影响,但血流速度的影响很小。而当血管位于目标治疗区域内部时,血流速度对可治疗焦域的影响不可忽略。上述研究结果可为HIFU实际临床治疗提供理论数据和参考依据。

The effect of large blood vessel next to the hepatic tumor on temperature distribution during HIFU tumor therapy is difficult to predict and achieve real-time monitoring which may result in clinical issues such as unexpected tumor residue or blood vessel injury. In order to predict the effect of large blood vessel on the HIFU hepatic tumor therapy, a 3-D simulation model based on tumor adjacent to large vessel was established. The Westerveh acoustic propagation equation and the Pennes bio-heat transfer equation were used to calculate the temperature field of simula- tion by the finite difference time domain （FDTD） method. The simulation results show that, when the large vessel is next to the target area, the shape, the size and the position of treatable focal region（ above 60℃） are mainly related to the position of the blood vessel, but the blood flow velocity is not. On the other hand, when the large vessel is lo- cated in target area, the effect of the blood flow velocity on treatable focal region is a non-ignorable factor. These re- suits can provide some theoretical data and reference basis during HIFU clinical therapy.