Beam steering of shock waves using 30 cm diameter bidimensional array

Abstract

Shock wave generators are now currently used for the treatment of renal stones. In all these generators the focal zone is determined by their geometrical parameters. We propose a piezo-composite shock wave generator with electronic focusing. The system is composed of a bidimensional array and its electronic hardware. The array is composed of 274 independent piezo-composite transducers arranged in a spherical shell 28 cm in diameter and focused at 190 mm. The electronic hardware includes 274×6 kV-impulse generators. The inter-delay of each channel can be adjusted between 100 ns to 100 μs by steps of 100 ns. Electronic focusing is efficient in an ellipsoidal region of about 4 cm in diameter and 12 cm in length, this volume is large enough to follow the displacement of the renal stones due to breathing during the treatment. In vitro results show that it is possible to destroy plaster balls located everywhere in this region