非线性声场下包膜微泡动力学与频率响应分析  

Dynamics and frequency response analysis of encapsulated microbubble under nonlinear ultrasound

作　　者：索鼎杰 纪镇祥 黄晓雲 靳杰 闫天翼 Suo Ding-Jie;Ji Zhen-Xiang;Huang Xiao-Yun;Jin Jie;Yan Tian-Yi(School of Medical Technology,Beijing Institute of Technology,Beijing 100081,China;Advanced Research Institute of Multidisciplinary Science,Beijing Institute of Technology,Beijing 100081,China)

机构地区：[1]北京理工大学医学技术学院,北京100081 [2]北京理工大学前沿交叉科学研究院,北京100081

出　　处：《物理学报》2024年第7期224-231,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12104049)资助的课题.

摘　　要：包膜微泡在非线性声场下的响应对高强度聚焦超声治疗具有重要意义.本文通过耦合Gilmore-Akulichev-Zener模型与脂质包膜的非线性模型,采用KZK方程仿真非线性声场,分析在不同超声频率、不同声压以及不同包膜材料的黏弹性下的微泡动力学行为和微泡振荡频率,并进一步对比了实际测量声场与KZK方程仿真声场下的微泡动力学行为和频率响应.研究结果表明:非线性声场会导致微泡壁的瞬时运动速率减小,声压和频率的改变对微泡动力学的影响与在线性声场中类似;包膜材料的不同可以使振荡频率中的谐波分量发生改变,其中包膜材料的弹性对微泡的频率响应影响较小,包膜的初始黏性和初始表面张力对微泡的振荡频率分布影响较大,当初始黏性越小时,二次分谐波的峰值越高,当初始表面张力越大时,主频的峰值越高.本研究进一步阐明非线性超声激励包膜微泡的微泡动力学,为包膜微泡在非线性声场下的频率响应分析奠定理论基础.Bubble dynamic behavior and frequency response of encapsulated microbubbles in nonlinear acoustic field is significant in applications such as tumor therapy,thrombolysis,tissue destruction,and ultrasonic lithotripsy.The acoustic cavitation effect includes stable cavitation and transient cavitation.The transformation from stable cavitation to transient cavitation requires a certain threshold,which is also called the transient cavitation threshold.Phospholipid-coated microbubbles are commonly used to enhance acoustic cavitation.However,the acoustic effects of different coating materials are not very clear,especially when considering the nonlinear effects caused by diffraction,scattering,and reflection during ultrasonic propagation.In this paper,the bubble dynamic behaviors and frequency responses of microbubbles under different frequencies,acoustic pressures,and viscoelastic properties of different shell materials are analyzed by coupling the Gilmore-Akulichev-Zener model with the nonlinear model of a lipid envelope and using the KZK equation to simulate the nonlinear acoustic field.At the same time,the influence of the coated material and nonlinear acoustic effects are considered.The bubble dynamic behavior and frequency response under the actually measured sound field are compared with those simulated by the KZK equation.The results show that the nonlinearity will lead the velocity of the microbubble wall to decrease,and when the pressure of ultrasound increases,the main frequency component of the microbubble oscillation increases,making the radial motion of the microbubble more violent.When the frequency changes,the closer the oscillation frequency of the microbubble is to the resonant frequency,the stronger the radial motion of the microbubble is.The coating material can change the harmonic component in the oscillation frequency.When the harmonic is close to the resonance frequency,the radial motion of the microbubble is enhanced.The elasticity of the coated material has almost no effect on the microbubble's fr

关 键 词：微泡动力学 非线性声场 包膜微泡 频率响应 

分 类 号：R312[医药卫生—基础医学]