A numerical investigation of the resonance of gas-filled microbubbles: resonance dependence on acoustic pressure amplitude
A numerical investigation of the resonance of gas-filled microbubbles: resonance dependence on acoustic pressure amplitude
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DOI：
10.1016/j.ultras.2004.04.001
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发表时间：
2004-12-01
期刊：
影响因子：
4.2
通讯作者：
McDicken, WN
中科院分区：
文献类型：
--
作者：
MacDonald, CA;Sboros, V;McDicken, WN
自由气泡的通用 Keller-Herring 方程通过特定术语进行扩充，以描述超声造影剂微泡中封装壳的弹性、粘度和厚度。采用分析气泡的声反向散射的数值研究来确定可以与通过分析考虑获得的线性近似值进行比较的共振频率，以增加驱动压力幅度。对诊断超声中使用的尺寸为 2 至 6 pm 的气泡进行计算，这些气泡浸入水和血液中并暴露于单色声波中，导致气泡经历稳定的空化，结果表明，随着压力幅度的增加，共振频率偏离线性近似值。研究发现，对于较大的气泡，共振向较低频率值的转变更为明显，计算值与线性近似值的差异高达 40%。该模拟的结果可能对制备具有特定所需特征（例如共振频率）的超声造影剂制剂有用。 (C) 2004 Elsevier B.V. 保留所有权利。
The general Keller-Herring equation for free gas bubbles is augmented by specific terms to describe the elasticity, viscosity and thickness of the encapsulating shell in ultrasound contrast agent microbubbles. A numerical investigation that analyses the acoustic backscatter from bubbles is employed to identify resonance frequencies that can be compared, for increasing driving pressure amplitude, with linear approximations obtained via analytical considerations. Calculations for bubbles of the size employed in diagnostic ultrasound, between 2 and 6 pm diameter, that are immersed in water and blood and exposed to monochromatic insonation, causing the bubbles to undergo stable cavitation, reveal that the resonance frequency diverges from the linear approximation as the pressure amplitude is increased. The shift in resonance, to lower frequency values, is found to be more pronounced for larger bubbles with the calculated value differing by up to 40% from the linear approximation. The results of this simulation might be potentially useful in preparation of formulations of ultrasound contrast agents with the specifically desired features, such as for instance resonance frequency. (C) 2004 Elsevier B.V. All rights reserved.