Beam steering of shock waves generated by a piezo-composite lithotriptor

In order to move the treatment area without displacing the shock wave generator, the authors propose a piezo-composite shock wave generator with electronic focusing. The array, is composed of 121 piezo-composite independent transducers arranged in a spherical shell 20 cm in diameter and focused at 190 mm. The electronic hardware includes 121×6 kV-impulse generators. The authors demonstrate experimentally that the steps of the inter-delay may be chosen up to 100 ns without a deterioration of the shock wave formation. Electronic focusing is efficient in an ellipsoidal region of about 4 cm in diameter and 6 cm in length, and the pressure at the focal point is 600×10 ⁵ Pa. In vitro results show that it is possible to destroy plaster balls located everywhere in the focal region