The problem of coupling in dry-head lithotripsy

Yuri A. Pishchalnikov, James A. McAteer, Joshua S. Neucks, Irina V. Pishchalnikova, James C. Williams

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


Recent in vitro studies have shown that air pockets can get trapped at the coupling interface of the treatment head in dry-head lithotripsy, and this can pose a significant barrier to transmission of shock wave energy to the focal zone. Breakage of model stones is very sensitive to the presence of air pockets at the coupling interface. The quality of routine coupling is highly variable, and it seems quite feasible that the way in which the coupling gel is applied may have a significant effect on the quality of coupling. Therefore, attempts to find the best coupling regime may be valuable to perform, and preliminary results of in vitro tests are presented in this report. Experiments were conducted using gel or castor oil as coupling agents. The test tank was coupled through a transparent Mylar membrane to the water-filled cushion of the treatment head, so that pockets of air trapped between the two coupling surfaces could be observed and photographed. It is shown that the quality of coupling can be improved by applying an excessive amount of gel to just the water cushion of the lithotripter, while applying gel to both the water cushion and the Mylar membrane typically gives poor coupling. Repeat decoupling and recoupling substantially degraded the quality of coupling, reducing shock wave energy density at the target by ∼80%. It was also observed that using castor oil as a coupling medium does not guarantee air-free coupling.

Original languageEnglish (US)
Title of host publicationRENAL STONE DISEASE
Subtitle of host publication1st Annual International Urolithiasis Research Symposium
PublisherAmerican Institute of Physics Inc.
Number of pages4
ISBN (Print)0735404062, 9780735404069
StatePublished - 2007
Event1st Annual International Urolithiasis Research Symposium - Indianapolis, IN, United States
Duration: Nov 2 2006Nov 3 2006

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Other1st Annual International Urolithiasis Research Symposium
CountryUnited States
CityIndianapolis, IN


  • Air pockets
  • Bubbles
  • Castor oil
  • Coupling
  • Coupling gel
  • Shock wave lithotripsy

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Pishchalnikov, Y. A., McAteer, J. A., Neucks, J. S., Pishchalnikova, I. V., & Williams, J. C. (2007). The problem of coupling in dry-head lithotripsy. In RENAL STONE DISEASE: 1st Annual International Urolithiasis Research Symposium (pp. 368-371). (AIP Conference Proceedings; Vol. 900). American Institute of Physics Inc..