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.