The 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 cavitation characteristics of SonoVue microbubbles.In this research,the effects of acoustic parameters or non-acoustic parameters on the dynamic response of the shell-less microbubbles triggered by pulsed ultrasonic are firstly analyzed,and thenthe cavitation characteristics of SonoVue microbubbles are theoretically analyzed by the Church model.The results show that the peak negative pressure threshold of stable cavitation of SonoVue bubbles is about 0.3 MPa,the energies of both the sub-harmonic andthe ultra-harmonics are positively correlated with the negative acoustic pressure but they are negatively correlated with the ultrasonic frequency.Based on the theoretical analysis,a tissue mimicking phantom was fabricated for holding SonoVue microbubbles.An experimental platform and a high-speed signal acquisition system were accomplished acoustic cavitation expsoure and measurement in static environment.After the signals were processed by time-frequency domains analyses,the extent of stable cavitation and inertial cavitation was characterized by the energies of ultraharmonics and broadband signals,respectively.We determined:1.In static environment,the peak negative pressure threshold of stable cavitation of SonoVue bubbles was about 0.25 MPa.When the peak negative pressure increased from 0.25 MPa to 0.5 MPa,the stable cavitation dose gradually increased.This result was in line with the theoretical analysis.For 0.1% SonoVue microbubbles concentration,the stable cavitation dose reached maximum.When the pulse duration was greater than 20 ?s,easily leading to the occurrence of stable cavitation,stable cavitation dose increased with the increasing pulse duration.However,the occurrence of the stable cavitation wass less dependent on the pulse repetition frequency,and the dose is also positively correlated with the pulse repetition frequency.2.The peak negative pressure threshold of inertial cavitation of SonoVue bubbles was about 0.4 MPa.The inertial cavitation dose increased with the increasing peak negative pressure,but the inertial cavitation period exhibited negatively correlation with the peak negative pressure.The pulse repetition frequency were positively correlated with both inertial cavitation dose and and inertial cavitation period.With the increaseing the concentration of SonoVue microbubbles,the inertial cavitation dose increased however,the inertial cavitation period gradually decreased.Finally,the customized high-speed data acquisition system was designed for cavitation signalanalysis,and the communications between FPGA and the host computer was preliminary realized by PCIE and USB3.0.