The principle of ultrasonic processor is not too mysterious and complicated. In short, it converts electric energy into sound energy through a transducer. This kind of energy changes into dense bubbles through a liquid medium (such as water). These bubbles burst rapidly, thus breaking up cells and other substances (commonly known as "cavitation effect").
The main effects of ultrasound on cells are thermal effect, cavitation effect and mechanical effect. Thermal effect: when ultrasound propagates in the medium, the friction hinders the molecular vibration caused by ultrasound, and transforms part of energy into local high heat (42-43 ℃), because the critical lethal temperature of normal tissue is 45.7 ℃. However, the sensitivity of tumor tissue is higher than that of normal tissue, so the metabolism of tumor cells is blocked at this temperature, and the synthesis of DNA, RNA and protein is affected, thus killing the cancer cells while the normal tissue is not affected. Cavitation effect: under ultrasound irradiation, vacuoles are formed in the organism, and mechanical shear pressure and turbulence are produced along with the vibration and violent explosion of vacuoles, resulting in tumor bleeding, tissue disintegration and necrosis. In addition, when the cavitation bubble breaks, it will produce instantaneous high temperature (about 5000 ℃), high pressure (up to 500 × 104pa), which can make the water vapor dissociate and produce OH and H. The redox reaction caused by OH and H can lead to polymer degradation, enzyme deactivation, lipid peroxidation and cell killing. Mechanical effect is the primary effect of ultrasound. In the process of ultrasound propagation, the media particles alternately compress and expand to form a pressure change, causing cell structure damage. The killing effect is closely related to the frequency and intensity of ultrasound.