Contactless comminution of concrements

DETAILED DESCRIPTION I claim: 1.
Method for contactfree comminution of a concrement in the body of a living being, including the steps of generating shock waves and focusing the shock waves as generated in a focal area located in a concrement, there being an axis of rotational symmetry regarding the shock wave generation and on which said concrement is located, the improvement of reducing a pressure drop in the focal area, by providing the steps of: controlling in radial direction in relation to the axis, the energization distribution for the production of pressure shock waves such that the shock wave pressure amplitude generated at a given point in time decreases with radial distance from said axis; and temporarily controlling the generation of the shock waves such that the amplitudes rise steeply at first and decay relatively slowly after having passed through a maximum.
2.
Method as in claim 1 said controlling step, including the step of varying the density of shock wave generation with distance from said axis.
3.
Apparatus for contact free comminution of concrements in the body of living being, including means for generating shock waves, and means for focusing said shock waves along an axis and into a concrement to be comminuted, the improvement of, first means for controlling the means for generating as to an energization distribution in a radial distance from the axis, wherein so that the amplitude of the shock waves declines with the radial distance from said axis; and second means for controlling the temporal generation of the shock waves so that the shock waves have a steep rise time followed by a more gradual decay.
4.
Apparatus as in claim 3 said generating means including calotta-spherically shaped energization means abutting an acoustic transmission medium such that upon energization of the generating means shock waves are directly produced in said transmission medium at the interface between the transmission medium and the means for generating, said first means being included in the generating means for obtaining a distribution variation of energization in said radial distance