The purpose of this application is to obtain funding to purchase an Imacon 200 high-speed camera system to be shared by 10 users (from 5 Universities) to pursue projects from 7 funded NIH grants. Our team of investigators conducts clinically relevant basic research of therapeutic and diagnostic ultrasound. Much of the work involves acoustic cavitation -- the formation, growth and violent collapse of bubbles -- on the scale of nanoseconds to milliseconds. Various tools are available for cavitation detection and quantification, but none is more powerful for visualizing bubbles in water than high-speed photography. We have managed to fund 3 brief rental periods during which we have collected data for 11 published papers. The Imacon 200 is the only camera capable of the spatial and temporal resolution, number of frames, and flexibility of adjustable inter-frame spacing required by our studies, but it is not for rent. The Imacon 200 will be available for shared use under the direction of the Camera Supervisor Dr. Lawrence Crum. Drs. Crum and Michael Bailey will use the camera to capture the shock wave interactions of the dual pulse lithotripter to characterize the lithotripter for potential in vivo use. Drs. Thomas Matula and Crum will image the response and rupture of echo contrast agents to identify acoustic parameters to optimize ultrasound image resolution. Dr. Tim Colonius plans to utilize camera images to verify a newly developed numerical predictor of bubble dynamics. Dr. Robin Cleveland looks to capture the acoustics and cavitation fields of new 3rd-generation lithotripters in an effort to correlate these characteristics with a recent decline in lithotripter efficacy and safety. Drs. Clyde Briant and Cleveland will investigate the rapid process of fracture in kidney stones. Dr. James McAteer will use the camera to find optimal parameters of voltage and rate of shock wave delivery in lithotripsy and Drs. James Williams and McAteer will record cavitation behavior in vitro under conditions that simulate the environment of the renal pelvis and kidney blood vessels to assess mechanisms of collateral damage in lithotripsy. Dr. Andrew Evan will observe cavitation activity in the kidney collecting system in vivo. Dr. Roy Martin hopes to capture the entrainment of bubbles, emulsification of blood, and the formation of a hemostatic paste in work to develop HIFU as a practical tool for trauma and surgical care.
