A preliminary evaluation of the effects of primary and secondary radiation forces on acoustic contrast agents
A preliminary evaluation of the effects of primary and secondary radiation forces on acoustic contrast agents
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DOI：
10.1109/58.656630
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发表时间：
1997-11-01
影响因子：
3.6
通讯作者：
Ferrara, KW
中科院分区：
文献类型：
--
作者：
Dayton, PA;Morgan, KE;Ferrara, KW
初级和次级辐射力由入射和散射超声场中的压力梯度产生。描述了这些力及其对实验参数的依赖性，并将初级辐射力的理论扩展到考虑脉冲行波。初级和次级辐射力都被证明对声波处理过程中微泡通过小容器的流动有显着影响。对于较小的传输声压，初级辐射力在 100 微米容器半径上产生微球位移，初级辐射力产生的位移显示出对脉冲重复频率的预期线性依赖性和对传输压力的非线性依赖性，次级辐射力产生微球的可逆吸引力和聚集，在大约 100 微米的距离上具有显着吸引力，次级辐射力的大小与间隔距离的平方成倒数，因此两个聚集体在接近一个聚集体时会加速另一方面，我们表明，这种力足以产生保持完整的聚集体，对于生理上适当的剪切率，声学传输的短暂中断可以立即破坏聚集体。
Primary and secondary radiation forces result from pressure gradients in the incident and scattered ultrasonic fields, These forces and their dependence on experimental parameters are described, and the theory for primary radiation force is extended to consider a pulsed traveling wave, Both primary and secondary radiation forces are shown to have a significant effect on the flow of microbubbles through a small vessel during insonation. The primary radiation force produces displacement of microspheres across a 100 micron vessel radius for a small transmitted acoustic pressure, The displacement produced by primary radiation force is shown to display the expected linear dependence on the pulse repetition frequency and a nonlinear dependence on transmitted pressure, The secondary radiation force produces a reversible attraction and aggregation of microspheres with a significant attraction over a distance of approximately 100 microns, The magnitude of the secondary radiation force is proportional to the inverse of the squared separation distance, and thus two aggregates accelerate as they approach one another, We show that this force is sufficient to produce aggregates that remain intact For a physiologically appropriate shear rate, Brief interruption of acoustic transmission allows an immediate disruption of the aggregate.