Various old and new shock‐wave applications require different shock‐wave beam characteristics

Abstract

Four different medical applications of shock waves and the appropriate pressure field will be discussed. Lithotripsy requires maximum shock‐wave energy at the stone. High‐pressure amplitudes and the total acoustical energy are the preferable parameters discussed for the disintegration effect. Improved kidney stone disintegration coincident with reduced side effect on the nephritic tissue was realized by a low‐angle focusing ellipsoid (LithoGold). In the treatment of soft tissue, unfocused shock waves allow the mechanical parameters like peak pressure and the energy density to be lowered dramatically. Activation of the body’s healing mechanisms are found after low pressure/ energy application by the release of growth factors, increased number of blood vessels, and the formation of new true tissue instead of scar tissue. For the treatment of diabetic skin ulcers an unfocused shock head is in controlled clinical studies within the USA. The last application relates to treating open heart muscle and requires a very small shock‐wave head. A very short focal distance (11 mm) is used. New blood vessels and the formation of new heart muscle cells are found after treatment. Technical and medical reasons for the different shock‐wave beam characteristics are provided.