key parameters and control of high focused piezo(二)

Publish Time: 2018-07-15     Origin: Site


The measurement of 250Khz hifu piezo is mainly the focus sound field characteristic - it is the focusing parameter. Because ultrasonic waves are prone to cavitation and nonlinear effects under water and human tissues, it is unpredictable factors, especially the focused sound field characteristics of high-power HIFU ultrasound piezo ceramic in the sound field of water and tissue are different from the focused sound field characteristics of the ideal sound field. Therefore, the measurement of the focused ultrasound and its sound field characteristics is much more difficult than that of the ultrasound diagnostic apparatus. It has passed the review of the national standard for high-intensity focused ultrasound therapy systems "industry standards and acoustic high-intensity focused ultrasound sound power and sound field characteristics". The basic ideas and practices of these two standards for focusing sound field characteristics and ultrasonic power measurement basins, Under the low power conditions (10% to 20% of full power output)


The three-dimensional scanning method of the hydrophone is used to find the sound pressure Hifu piezoelectric crystal position, and the focused sound field is scanning and measured, and the geometric parameters of the focal spot are calculated; the ultrasonic power is measured by hydrophone or radiation force method, and the maximum high focus piezoelectric sensor is obtained according to the relevant formula.The fact is that there is a big difference between the focused sound field characteristics under the high power conditions, the sound field characteristics are under low power conditions.The calibration and resistance of the hydrophone is also compared with the actual problem, the radiation method is more suitable for the measurement of small power, and the error is relatively large. Therefore, whether the ultrasonic power obtained by measuring the actual situation is worthy of discussion.


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