Acoustic droplet vaporization (ADV) plays an important role in focused ultrasound theranostics. Better understanding of the relationship between the ultrasound parameters and the ADV nucleation could provide an on-demand regulation and enhancement of ADV for improved treatment outcome. In this work, ADV nucleation was performed in a dual-frequency focused ultrasound configuration that consisted of a continuous low-frequency ultrasound and a short high-frequency pulse. The combination was modelled to investigate the effects of the driving frequency and acoustic power on the nucleation rate, efficiency, onset time, and dimensions of the nucleation region. The results showed that the inclusion of short pulsed high-frequency ultrasound significantly increased the nucleation rate with less energy, reduced the nucleation onset time, and changed the length–width ratio of the nucleation region, indicating the dual-frequency ultrasound mode yields an efficient enhancement of the ADV nucleation, compared to a single-frequency ultrasound mode. Furthermore, the acoustic and temperature fields varied independently with the dual-frequency ultrasound parameters. This facilitated the spatial and temporal control over the ADV nucleation, and opens the door to the possibility to realize on-demand regulation of the ADV occurrence in ultrasound theranostics. In addition, the improved energy efficacy that is obtained with the dual-frequency configuration lowered the requirements on hardware system, increasing its flexibility and could facilitate its implementation in practical applications.

声学液滴汽化 (ADV) 在聚焦超声治疗中起着重要作用。更好地了解超声参数与 ADV 成核之间的关系可以提供按需调节和增强 ADV 以改善治疗结果。在这项工作中，ADV 成核是在双频聚焦超声配置中进行的，该配置由连续低频超声和短高频脉冲组成。该组合被建模以研究驱动频率和声功率对成核速率、效率、起始时间和成核区域尺寸的影响。结果表明，短脉冲高频超声的加入显着提高了成核率，且能量较低，成核起始时间缩短，并改变了成核区域的长宽比，表明与单频超声模式相比，双频超声模式可有效增强 ADV 成核。此外，声场和温度场随双频超声参数独立变化。这促进了对 ADV 成核的空间和时间控制，并为实现超声治疗中 ADV 发生的按需调节的可能性打开了大门。此外，通过双频配置获得的能量效率提高降低了对硬件系统的要求，增加了其灵活性，并有利于其在实际应用中的实施。表明与单频超声模式相比，双频超声模式产生了 ADV 成核的有效增强。此外，声场和温度场随双频超声参数独立变化。这促进了对 ADV 成核的空间和时间控制，并为实现超声治疗中 ADV 发生的按需调节的可能性打开了大门。此外，通过双频配置获得的能量效率提高降低了对硬件系统的要求，增加了其灵活性，并有利于其在实际应用中的实施。表明与单频超声模式相比，双频超声模式产生了 ADV 成核的有效增强。此外，声场和温度场随双频超声参数独立变化。这促进了对 ADV 成核的空间和时间控制，并为实现超声治疗中 ADV 发生的按需调节的可能性打开了大门。此外，通过双频配置获得的能量效率提高降低了对硬件系统的要求，增加了其灵活性，并有利于其在实际应用中的实施。声场和温度场随双频超声参数独立变化。这促进了对 ADV 成核的空间和时间控制，并为实现超声治疗中 ADV 发生的按需调节的可能性打开了大门。此外，通过双频配置获得的能量效率提高降低了对硬件系统的要求，增加了其灵活性，并有利于其在实际应用中的实施。声场和温度场随双频超声参数独立变化。这促进了对 ADV 成核的空间和时间控制，并为实现超声治疗中 ADV 发生的按需调节的可能性打开了大门。此外，通过双频配置获得的能量效率提高降低了对硬件系统的要求，增加了其灵活性，并有利于其在实际应用中的实施。