高强度聚焦超声治疗的实时被动空化检测系统及其实验研究

高强度聚焦超声（High Intensity Focused Ultrasound，HIFU）所致空化效应在临床应用中扮演着重要角色，对HIFU临床治疗过程中的空化活动进行实时监测，结合数据分析与治疗过程中实时反馈，可进一步提高HIFU治疗的安全性和有效性。在现有HIFU临床治疗系统的基础上，将两个被动空化检测探头与HIFU换能器集成。在Matlab环境下开发了独立的上位机控制系统，基于以太网通信和虚拟仪器技术，实现了上位机的自动测试，融合被动空化检测系统与HIFU临床治疗系统，对空化所致声发射信号进行实时监测。通过HIFU辐照离体组织实验对该系统进行了测试验证，各种声功率条件下的超声辐照离体组织监测过程中，次谐波幅值与宽带噪声的均方根被实时可视化，用于监测空化的发生；次谐波与宽带噪声均方根的积分曲线斜率用于表征组织焦域处的相对空化强度。实验结果表明，该系统可满足临床治疗过程中对空化活动进行实时监测和数据分析处理的需求，为深入研究实际临床治疗中空化效应和实时反馈提供了一种有力的研究手段。

A real-time passive cavitation detection system and its experimental study for HIFU therapy

Cavitation effect caused by high intensity focused ultrasound (HIFU) plays an important role in clinical application. Real-time cavitation monitoring combined with data analysis and real-time feedback during HIFU clinical treatment can improve the safety and effectiveness of HIFU treatment. Based on the existing HIFU clinical treatment system, two PCD probes detectors are integrated with HIFU transducer. An independent upper computer control system is developed by Matlab, and the automatic tests of upper computer are realized by Ethernet communication and virtual instrument technology. Passive cavitation detection system is combined with HIFU clinical treatment system for real-time monitoring the acoustic emission of cavitation. The system is tested while HIFU irradiating the in vitro tissues. During monitoring the in vitro tissues treated under various ultrasonic powers, the subharmonic amplitude and root mean square of broadband noise are visualized in real time to monitor the occurrence of cavitation, and the slopes of the integral curves of subharmonic and RMS of broadband noise are used to characterize the relative cavitation intensity in the focal region of the tissue. The experimental results show that the system can meet the needs of real-time cavitation monitoring and data analysis and processing in clinical treatment, and provides a powerful means to deeply study the effect of cavitation and real-time feedback in actual clinical treatment.