利用换能器电信号相位特征实时监测高强度聚焦超声治疗中的声空化

Real-time monitoring of acoustic cavitation in high intensity focused ultrasound based on phase characteristics of transducer electrical signals

高强度聚焦超声(HIFU)激发的声空化可加速靶组织的热消融,但声空化的实时监测是一个亟需解决的问题。利用HIFU换能器驱动电信号的相位差与电阻抗之间的数学模型,建立了HIFU辐照及换能器驱动电信号、声空化信号实时检测实验系统,探究了HIFU辐照离体牛心组织过程中,换能器驱动电信号的相位差与B超影像灰度变化及宽频水听器检测到的次谐波和宽带噪声信号的变化规律。结果表明:当声空化发生时,换能器驱动电信号相位差的变化与水听器检测到的次谐波和宽带噪声信号变化具有一致性,通过相位差的变化可实现HIFU辐照靶组织中声空化的实时、精准监测,这为HIFU所致声空化的实时监测提供了一种有应用前景的解决方案。

Acoustic cavitation induced by high intensity focused ultrasound(HIFU)can accelerate the thermal ablation of the target tissue.However,real-time monitoring of acoustic cavitation caused by HIFU is an urgent problem to be solved.The phase characteristics of the electrical signal of the HIFU transducer are established to analyze the real-time monitoring of acoustic cavitation.Under different HIFU excitation voltages,experimental research about real-time monitoring of acoustic cavitation in isolated bovine heart tissue irradiated by HIFU has been carried out.In addition,the phase difference of driving electrical signal is compared with the grayscale change of the B-ultrasound image and change results of subharmonic and broadband noise detected by broadband hydrophone.The research results show that when acoustic cavitation occurs,the change of phase difference of driving electrical signal has good consistency with the change of subharmonic and broadband noise detected by hydrophone.By the change of phase difference,real-time and accurate monitoring of the duration of acoustic cavitation occurring in target tissue irradiated by HIFU can be achieved,which provides a promising solution for real-time monitoring of acoustic cavitation caused by HIFU.