Method and apparatus for generating focused ultrasonic waves with surface modulation

A method for generating focused ultrasonic waves over a focal zone (5) to produce biological lesions comprises the activation of a plurality of ultrasonic transducer elements (3) distributed over an emission surface (4) to respectively emit a plurality of focused ultrasonic waves in the focal zone (5), while crossing through the propagation mediums (Ei) at different acoustic attenuations, characterized in that:

• a target zone (7) in which homogenization of the energy contributions of the ultrasonic waves emitted by the ultrasonic transducer elements is desired is chosen,
• the focal effect and the acoustic attenuations of the ultrasonic waves on their paths between the target zone (7) and the ultrasonic transducer elements are determined (3),
• the focal effect and the acoustic attenuations of the ultrasonic waves are compensated, with ultrasonic transducer elements (3), at least some of which have non-identical emission surfaces so that in the target zone (7), the energy contribution of the ultrasonic waves emitted by the different ultrasonic transducer elements (3) are substantially identical.