Page 129 - 201903

第 38 卷 第 3 期 Vol. 38, No. 3
2019 年 5 月 Journal of Applied Acoustics May, 2019

⋄ 研究报告 ⋄

剪切波对HIFU经颅聚焦形成温度场影响的

数值仿真研究

张艳秋 张 浩 孙天宇 菅喜岐 †

(天津医科大学生物医学工程与技术学院 天津 300070)

摘要 在高强度聚焦超声经颅治疗时，既有纵波又有剪切波，为了保障该治疗方法的安全有效性，有必要分析
剪切波对 HIFU 治疗温度场的影响。该文基于人体头颅 CT 数据和曲率半径为 150 mm 的 256 阵元的半球相
控换能器建立三维高强度聚焦超声经颅声波传播模型，利用时域有限差分法结合 Westervelt 声波非线性传播
方程、动量方程、质量守恒方程和 Pennes 生物热传导方程数值仿真其形成温度场，研究在相同输入功率、不同
聚焦角度条件下对应阵元数进行激励时，剪切波对换能器形成温度场的影响。结果表明，随换能器聚焦角度减
小，在几何焦点处形成的焦域面积逐渐增大，考虑剪切波形成的温度场达到 65 C 所需时间逐渐延长，焦点前
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移程度越大；在相同聚焦角度条件下，考虑剪切波的温度场达到 65 C 所需时间更短，旁瓣更少，在颅骨处的温
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度更高，对焦点前移几乎没有影响；随换能器聚焦角度减小，考虑剪切波的模型形成的焦域面积变化范围更大；
幂指数函数形式对不同聚焦角度下焦域面积大小的拟合优度高，可预测不同聚焦角度换能器形成的焦域面积。
关键词 高强度聚焦超声，剪切波，聚焦角度，温度场，时域有限差分
中图法分类号: R318 文献标识码: A 文章编号: 1000-310X(2019)03-0411-08
DOI: 10.11684/j.issn.1000-310X.2019.03.018

Numerical simulation of the effect of shear wave on the temperature field of

HIFU transcranial focusing

ZHANG Yanqiu ZHANG Hao SUN Tianyu JIAN Xiqi
(Department of Biomedical Engineering and Technology, Tianjin Medical University, Tianjin 300070, China)

Abstract Ultrasound includes long wave and shear wave. In order to ensure the safety and effectiveness of the
treatment, it is necessary to analyze the effect of shear wave on field area of high intensity focused ultrasound
(HIFU) treatment. In this paper, a three-dimensional HIFU transcranial acoustic wave propagation model is
established based on human skull CT data and a 256-array hemispherical phase-controlled transducer with a
radius of curvature of 150 mm. The Westervelt nonlinear acoustic propagation equation and momentum equa-
tion, as well as mass conservation equation and Pennes bioheat equation are used to calculate the temperature
field by finite difference time domain (FDTD). The effect of shear waves on the transducer temperature field
is investigated when the corresponding input elements are excited at different focus angles. The results show
that, as the focus angle of the transducer decreases, the area of the focal region formed at the geometric focus
gradually increases, as well as the time required for the temperature field formed by the shear wave to reach
65 C is gradually extended, and the focus advances. Under the same focus angle condition, the time required
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2018-10-15 收稿; 2018-12-28 定稿
作者简介: 张艳秋 (1993- ), 女, 黑龙江哈尔滨人, 硕士研究生, 研究方向: 超声医学。
† 通讯作者 E-mail: jianxiqi@tmu.edu.cn