Shock wave characteristics in liquids and extracorporal lithotripsy

Abstract

Reliable determinations of shock wave parameters such as risetime, pulse width, and positive and negative pressure amplitudes are prerequisites for a study and comparison of different stone destruction mechanisms in lithotripsy. In comparing stone destruction mechanisms, it is found that the fiber-optic probe hydrophone is ideally suited for reliable shock-wave measurements, especially also in the negative pulse range. Different stone destruction mechanisms as a direct action of the shock wave penetrating into the stone, the sound soft reflection, i.e., the Hopkinson effect, the importance of cavitation, and finally the action of evanescent waves in the stone caused by the passing pressure wave in the liquid are discussed in their dependence on shock wave parameters. The results are compared with experiment.