Initial cavitation threshold distribution rebuilding method based on ultrasonic active cavitation imaging

Abstract

The invention discloses an initial cavitation threshold distribution rebuilding method based on ultrasonic active cavitation imaging. The method comprises the steps of: firstly, emitting a synchronizing signal to a cavitation power source and a full-digitalized ultrasonic imaging device by a signal generator; stimulating a medium through continuous variable power to generate the cavitation by the power source; simultaneously emitting a plane wave and receiving a cavitation echo signal by the full-digitalized ultrasonic imaging device; achieving a cavitation bubble distribution imaging sequence with high resolution and high signal-to-noise ratio through the echo signal by synthetic aperture time delay, correlation coefficient adaptive beam synthesis and interframe decorrelation SSD (steady-state distribution); carrying out region segmentation and extracting a sub-area power intensity curve (PIC) from a sequence image; setting an intensity threshold in the PIC; taking the power corresponding to the intensity threshold as a cavitation initial threshold; and rebuilding the initial cavitation threshold space distribution by pseudo color coding after the initial threshold of each sub-area is obtained. By adopting the method disclosed by the invention, the intuitive image analysis is provided for a cavitation bubble distribution state under the effects under different powers and different parameters; and the foundation is provided for the cavitation analysis of different mediums.

Description

technical field [0001] The present invention relates to the technical field of ultrasonic detection and ultrasonic imaging, and in particular to a cavitation initiation threshold distribution reconstruction method based on ultrasonic active cavitation imaging. Based on ultrasonic active cavitation imaging with high temporal resolution and high signal-to-noise ratio, a high-frequency ultrasonic reconstruction method for spatial distribution of cavitation onset threshold is proposed. Background technique [0002] Cavitation refers to the activation of cavitation nuclei in liquids under the action of external energy (heat / force), which manifests as a series of dynamic processes such as oscillation, growth, shrinkage and even collapse of tiny nuclei. The main mechanisms of release, gene transfection, in vitro lithotripsy, thrombolysis, hemostasis, hyperthermia, and thermal ablation of tumors. The cavitation formation process is accompanied by the generation of cavitation bubble...

AI Technical Summary

Problems solved by technology

[0004] Active cavitation detection uses the transducer to actively emit acoustic signals to act on the target area, and reflects the cavitation state by detecting the backscattered echo of cavitation bubbles. The most basic method is B-ultrasound imaging, and the B-ultrasound imaging process determines the The quasi-real-time nature of ultra-images, that is, different scan lines of each frame of image are not obtained at the same time, and the imaging frame rate is also limited to tens of Hz, which cannot realize the acquisition of transient behavior of cavitation bubbles

The Fink group of INSERM in France proposed a plane wave composite fast ultrasonic imaging method for the detection and imaging of cavitation nucleation. This method realizes high frame rate real-time imaging through plane wave emission, and proposes the composite of coherent waves at different angles to improve the imaging signal-to-noise ratio, but the signal-to-noise ratio The improvement sacrifices the imaging frame rate to a certain extent

[0005] The cavitation threshold is mostly studied in theoretical modeling, including the initiation of cavitation (steady-state cavitation) and the collapse of cavitation (transient cavitation). The experiment is limited to the optical high-speed / Ultrahigh-speed photography and studies of sonoluminescence / sonochemiluminescence for cavitational collapse, both of which are limited by the transparency of the medium

The PCD method is also used to detect broadband noise signals to study the cavitation collapse threshold, but PCD cannot provide spatial distribution information and cannot be used to detect the cavitation onset threshold

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