Microbubble translations driven by ultrasound-induced radiation forces can be beneficial for applications in ultrasound molecular imaging and drug delivery. Here, the effect of size range in microbubble populations on their translations is investigated experimentally and theoretically. The displacements within five distinct size-isolated microbubble populations are driven by a standard ultrasound-imaging probe at frequencies ranging from 3 to 7 MHz, and measured using the multi-gate spectral Doppler approach. Peak microbubble displacements, reaching up to 10 μm per pulse, are found to describe transient phenomena from the resonant proportion of each bubble population. The overall trend of the statistical behavior of the bubble displacements, quantified by the total number of identified displacements, reveals significant differences between the bubble populations as a function of the transmission frequency. A good agreement is found between the experiments and theory that includes a model parameter fit, which is further supported by separate measurements of individual microbubbles to characterize the viscoelasticity of their stabilizing lipid shell. These findings may help to tune the microbubble size distribution and ultrasound transmission parameters to optimize the radiation-force translations. They also demonstrate a simple technique to characterize the microbubble shell viscosity, the fitted model parameter, from freely floating microbubble populations using a standard ultrasound-imaging probe.

中文翻译：

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大小范围对微气泡群体中超声诱导的翻译的影响。

由超声引起的辐射力​​驱动的微泡翻译对于超声分子成像和药物递送中的应用可能是有益的。在这里，实验和理论上研究了微气泡群体的大小范围对其翻译的影响。由一个标准的超声成像探头在3至7 MHz的频率范围内驱动五个不同的大小隔离的微气泡种群内的位移，并使用多门频谱多普勒方法进行测量。峰值微气泡位移，可达10μ发现每个脉冲μm可以从每个气泡总体的共振比例描述瞬态现象。气泡位移的统计行为的总体趋势（由识别出的位移的总数来量化）表明，气泡数量之间的显着差异是传输频率的函数。在实验和理论之间找到了很好的协议，其中包括模型参数拟合，进一步通过单独测量单个微泡以表征其稳定脂质壳的粘弹性来进一步支持。这些发现可能有助于调整微泡尺寸分布和超声传输参数，以优化辐射力平移。他们还展示了一种简单的技术来表征微泡壳的粘度，