Sound source and focusing method of HIFU treatment

In the HIFU treatment, whether it is extracorporeal to shock wave lithotripsy treatment equipment or Ultrasound HIFU piezo tumor treatment equipment,Ultrasonic generation and focusing devices are the core components. At present, there are three main sources of high-intensity focused ultrasound.A different method of occurrence was adopted.

(l) Liquid-electric type refers to the use of electrode spark discharge or explosive in the metal sphere of the water-filled ellipsoid.The method of ultrasound piezo crystal produces a spherical shock wave that is reflected by the inner surface of the ellipsoid and converges.To the second focus, this form of sound source is mainly used for extracorporeal shock wave lithotripsy.

(2) piezoelectric sound sources are mainly in two forms, showing that hundreds or even thousands of ceramic piezoelectric vibrators are embedded in the spherical shell or the piezoelectric ceramic sheets are directly ground into.

The sound source of HIFU ultrasound piezoelectric sensor is the spherical crown constitutes the sound source of focused ultrasound, and adopts the spherical self-focusing method to make the emitted spherical pulse ultrasonic wave naturally converges, which has higher performance requirements for the manufacturing process and the power amplifier circuit. The energy device is generally treated by mechanical scanning, and has the disadvantages of large volume, low electroacoustic efficiency and unadjustable focal length. The piezoelectric sound source is a piezoelectric vibrator that is directly coupled to a large metal acoustic lens.The way the acoustic lens is focused, the electrical hifu piezoelectric sensor is generated by the piezoelectric vibrator are focused, but the lens itself absorbs sound.The high temperature generated will deform the lens, and the focusing effect of the ultrasonic lens is not only related to the medium, but also
related to the lens material, interface reflection and acoustic lens attenuation will also cause loss of acoustic energy, and the focusing of the acoustic lens.The electroacoustic efficiency is low and the focal length is not adjustable. The sound source can be used for both HIFU tumor treatment and body external shock wave treatment.

The electromagnetic type shows the use of a strong current pulse through a planar coil, and the generated magnetic field pushes a metal film.a plane pressure wave is generated in the water pipe which is in contact with it, and then ultrasonic piezo hifu is focused by an acoustic lens, or a shock wave is generated by a coil on the hollow cylinder table to radiate perpendicular to the axis direction, and the cylindrical wave formed is passed through a spiral parabolic microscope focus. The electromagnetic shock wave has high focusing efficiency and there is no scattering shock wave; the shock wave source can be continuously used without frequent troubles of replacing the electrode, and is currently mainly applied to extracorporeal shock wave .