脉冲超声激励下SonoVue微泡的瞬态空化特性

将SonoVue微泡从临床疾病诊断拓展至治疗引起了诸多研究人员的兴趣。为了平衡治疗效率和生物安全性,深入理解声学参数和SonoVue微泡瞬态空化的关系至关重要。本研究自行制备仿体容器放置SonoVue微泡,使用1 MHz发射换能器激励其产生空化效应,另一个7.5 MHz的聚焦换能器接收声信号,经放大及高速数据采集后送上位机处理。通过深入分析信号的时频域特征,我们提出以宽带信号的能量及其随时间变化曲线的半高宽来表征瞬态空化的剂量(ICD)和相对持续时间(ICP),并确定:瞬态空化的发生和ICD依赖于峰值负声压,但ICP随峰值负声压的增加而减小;脉冲重复频率和脉冲持续时间都和ICD及ICP正相关;且脉冲持续时间的影响较大。这些结果有望为SonoVue微泡的治疗应用提供理论支持。

The inertial cavitation characteristics of SonoVue microbubbles mediated by pulsed ultrasound

Extending the clinical application of SonoVue microbubbles from disease diagnosis to therapy is currently attracting considerable research interest. To coordinate therapeutic efficiency and bio-safety, it is important to comprehensively understand the relationship between acoustic parameters and the inertial cavitation characteristics of SonoVue microbubbles. A tissue phantom was fabricated to hold SonoVue bubble solution, a 1 MHz plane transducer and another7.5 MHz focused transducer were employed for triggering cavitation of SonoVue bubbles and receiving acoustic signal,respectively. Then the signal was amplified and recorded by a high-speed AD. After the time and frequency domains were deeply analyzed by fast flourier transform, the total energy and duration of the broadband signals were used to evaluate the inertial cavitation dose(ICD) and inertial cavitation period(ICP) of SonoVue bubbles.We found:the onset and dose of inertial cavitation of SonoVue bubbles were dependent on the peak negative pressure, and ICP decreased with the increasing peak negative pressure. Both the pulse repetition frequency and pulse duration were positively correlated with ICD and ICP. These results can provide useful information for therapeutic applications of the SonoVue microbubbles.