Radiology, Vol 177, 157-161, Copyright © 1990 by Radiological Society of North America
Cavitation effects during lithotripsy. Part I. Results of in vitro experiments
RK Zeman, WJ Davros, BS Garra and SC Horii
Department of Radiology, Georgetown University Medical Center, Washington, DC 20007.
Cavitation effects and microbubble formation are due to the rarefactive
(negative pressure) component of shock waves. The in vitro application of
shock waves generated by a commercial lithotriptor to an anthropomorphic
phantom showed that stone fragmentation occurred more completely in fluid
media that support cavitation than in a solid agar- graphite gel. Various
fluids (saline, iodinated contrast material, bile) supported different
degrees of cavitation. Bile exhibited cavitation at low energy and gave
rise to intense microbubble formation at 19 kV. Cavitation increased
dramatically with an increase in the rate of generation from 1.0 to 1.8
shock waves per second. The authors conclude that during biliary
lithotripsy the environment of a stone will influence the extent of
cavitation and fragmentation.
