First temporal and spatial quantification of single-shot electrohydraulic lithotripsy in vitro.

Single electrohydraulic lithotripsy (EHL) discharges from a human ureter were analyzed with a mechanical high-speed motion analysis camera. We found a cavitation bubble, at 650 mJ, 4-11 mm in size, with a lifetime of 400-500 microseconds. Varying sizes and lifetimes were found using single-shot analysis, as well as in different shot-sequences. This supports similar observations by recent investigations of cavitation bubble size with high-shutter-speed videofilm, which have depicted events at shutter speeds of 4000/s, i.e., an approximate exposure time of 250 microseconds. Due to the occurrence of high-voltage interference from the EHL high-voltage generator, no other technical electronic event timing equipment has so far been available capable of mechanical high-speed film motion analysis, while at the same time avoiding high-voltage interference.