Measurement of lithotripsy pulses through biological media

Lithotripsy is now the method of choice for the treatment of renal calculi. The mechanism of destruction is not clearly understood, and detailed knowledge of the shock-wave characteristics at the calculus would aid understanding of the phenomenon. Current methods of measuring the pressure pulse by observing it through a water path are not well characterized, and the results may not represent the actual pressure fluctuations produced in vivo. In order to determine the actual pressure pulse experienced at the site of the calculus, measurements have been made through a variety of biological media. The results show that there are considerable differences between measurements taken through a water path and through biological media. This paper describes the pressure fluctuations in the time domain. The implications of the results for lithotripsy are discussed.