[Non-thermal non-cavitational effects of ultrasound]

The non-thermal, non-cavitational (NTNC-) effects of medical ultrasound are based essentially on the direct and indirect effects of the sound radiation pressure. This article introduces the biophysics of the basic mechanisms and describes possible clinical implications using selected examples. It has been determined that generally no additional risks ensue through the effects of NTNC used purely for diagnostic purposes. Significant effects can only be detected under the conditions which prevail during therapeutic exposure. The question as to whether the pulse Doppler technique is completely harmless cannot be answered conclusively at this time. The synergetic effects between ultrasound and contrast media have not yet been examined thoroughly.