Shock Wave Res. Ctr., Inst. Fluid Sci., Tohoku Univ., Sendai, Japan
Miyagi Cancer Ctr.
Tohoku Univ., Sendai, Japan
Among the possible causes of ESWL tissue damage, the interaction of shock waves with cavitation bubbles is believed to be the most responsible. A series of analog experiments has been carried out for clarifying the mechanism of tissue damage during ESWL. Interactions of shock waves with single air bubbles in water were examined, including the formation of a rebound shock wave and the generation of liquid microjets. The collapse of air bubbles which were attached to gelatin walls and exposed to shock waves was quantitatively observed using double-exposure holographic interferometry and high-speed cinematography. In these analog experiments, shock waves were created via microexplosives: 10-mg silver azide pellets were pasted on the tip of an optical fiber and detonated with the radiation of a pulsed YAG laser beam. Details of the bubble collapse were well resolved. More complex materials analogous to human tissue have been tested and will be presented also.