Cavitation damage with the dual-reflector lithotripter
EMSL Project ID
2023
Abstract
Most patients treated for kidney stones undergo extracorporeal shock wave lithotripsy (ESWL), a method by which high intensity shock waves are focused at the site of the stone. Although ESWL is the most favorable method for treating stones, there is evidence to indicate that substantial damage may be occurring to healthy tissue during treatment. A primary mechanism for damage to both the stone and soft tissue may be shock wave induced cavitation, the violent growth and collapse of microscopic bubbles. When a cavitation bubble collapses near a rigid surface, it generates a jet of water directed toward the surface with enough force to cause damage even to hard metals. The current project examines methods of controlling the cavitation field. We have promising evidence that two confocal lithotripters, fired simultaneously, generate a localized cavitation field that may increase the rate of stone breakup while mitigating damage to surrounding tissue. Our experiments are performed in a research electrohydraulic lithotripter. One method we use for obtaining an image of the cavitation field in water involves placing a thin metal foil at the focus of the lithotripter. The cavitation bubbles generated by the shock waves collapse against the foil, leaving a pattern of pits, varying in depth from tens to hundreds of micrometers. We would like to use the Zygo NewView 200 profilometer, available at EMSL, to measure the depth of the pits generated in aluminum foil. The objective is to quantify and compare cavitation damage between the dual-reflector lithotripter and a conventional lithotripter. We explored several other options for making these measurements and subsequently concluded that a non-touch profilometer is the best tool for our needs. Glen Dunham, tool supervisor, has already made a measurement on one of our sample foils to verify that this particular profilometer will meet our needs in terms of sample size, resolution and ease of use.
Project Details
Project type
Exploratory Research
Start Date
2000-08-30
End Date
2000-09-30
Status
Closed
Released Data Link
Team
Principal Investigator