Ultrasonic heating appts. for treatment of deep biological tissue - has piezoelectric plate divided into annular radiation zones of equal width divided by grooves

摘要

The device is used to locally heat biological tissues using an ultrasonic radiation, from an electromechanical transducer associated with an electrical generator whose oscillation frequency is predetermined. The transducer is a half-wave of the half wave types and includes a plate (1) made from a piezoelectric material. One (2) of its faces has concentric annular grooves (4) of which the spacing is approximately equal to the wavelength in water of the ultrasonic radiation. The other face (3) of the plate (1) is smooth. The radiating annular zones between the grooves (4) are fitted with electrodes which are in contact with both faces (2,3). The electrical generator includes a series of adjustable phase shifters to feed the electrodes with voltages whose phase is adjustable in order to focalise the radiation (9) inside the biological tissues (8).