Use of Dual-Pulse Lithotripter to Generate a Localized Intensified Cavitation Field
- Washington University
- 8408
Localizing cavitation to the kidney stone in extracorporeal shock wave lithotripsy may be desirable since cavitation appears to play a major role in both stone comminution and renal tissue damage. A method has been developed to localize and intensify cavitation damage in vitro. Cavitation fields in water were filmed with a high-speed digital video camera. In a conventional lithotripter (CL), the shock wave produced by a single source creates a 2 x 10 cm cylindrical cloud of bubbles in water. Bubbles in the CL field collapse simultaneously along the focal axis to produce a nearly uniform 1-mm x 8-cm line of pits in 25- mm-thick aluminum foil. Our dual-pulse lithotripter (DPL) uses two shock wave sources, facing each other, confocal, and triggered simultaneously to create a 4 x 5 cm cylindrical cloud of bubbles that collapse over a range of times and strengths such that the greatest pit damage on foils is contained within a few square millimeters of the focus. The time for bubbles to grow and collapse was measured with a focused hydrophone and compared with calculations based on the Gilmore equation. Pressure doubling due to synchronous arrival of the two pulses at the focus created increased bubble growth and increased foil pit depth. Asynchronous timing between the two pulses elsewhere in the DPL field resulted in disruption of radial dynamics and negligible pitting to foils. Translation of bubbles was also investigated, both numerically and experimentally. While net translation was calculated to be ,0.3 mm in all cases, the rapid
- Research Organization:
- Pacific Northwest National Lab., Richland, WA (US), Environmental Molecular Sciences Lab. (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 15004151
- Journal Information:
- Journal of the Acoustical Society of America, Vol. 110, Issue 3; Other Information: PBD: 1 Sep 2001; ISSN 0001-4966
- Country of Publication:
- United States
- Language:
- English
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State of the art extracorporeal shock wave lithotripsy