Piezoelectric transducer for destruction of concretions inside the body

A piezoelectric transducer for destruction of concretions inside the body. The transducer essentially comprises a spheroidal cap having piezoelectric ceramic elements situated at its radially inner front side. To prevent overpressure pulses radiated at the front side of the transducer being followed by underpressure pulse reflected from the rear side of the cap, the cap is produced from metal, preferably from a copper alloy. The impact wave resistances of the cap metal and of the ceramic material should largely correspond. Furthermore, the rear-side surface of the rear wall of the cap is so shaped geometrically and/or provided with a coating, that the sonic waves reflected therefrom are no longer focussed.