THE SPATIAL-DISTRIBUTION OF CAVITATION INDUCED ACOUSTIC-EMISSION, SONOLUMINESCENCE AND CELL-LYSIS IN THE FIELD OF A SHOCK-WAVE LITHOTRIPTER

This study examines the spatial distribution of various properties att ributed to the cavitation field generated by a shock wave lithotripter . These properties include acoustic emission and sonoluminescence, whi ch result from violent bubble collapse, and the degree of cell lysis i n vitro, which appears to be related to cavitation. The acoustic emiss ion detected with a 1 MHz, 12 cm diameter focused hydrophone occurs in two distinct bursts. The immediate signal is emitted from a small reg ion contained within the 4 MPa peak negative pressure contour. A secon d, delayed, burst is emitted from a region extending further along the beam axis. The delay between these two bursts has also been mapped, a nd the longest delay occurs at positions close to the regions of maxim um peak negative pressure. Sonoluminescence from both single and multi ple shocks occurs in a broader region than the acoustic emission but t he measurement technique does not allow time resolution of the signal. Cell lysis occurs in a relatively small region that correlates closel y with the immediate acoustic emission for a shock propagating in a ge latine solution.