Analysis of two successive shock waves generated by a compact generator using underwater pulse electric discharge for medical application

This report presents on studying of two kinds of underwater shock waves generate by a compact generator using underwater pulsed electric discharges in saline water and their medical application. The water used in this study is aqueous solutions of sodium chloride which is substitute for application to human tissue, while underwater shock waves can propagate in the tissue with low reflection between the solutions and the tissue boundary. The diameter of the compact reflector was 20 mm. Two kinds of underwater shock waves, generated by plasma expansion and bubble collapse, were studied by two methods. One method employed time-resolve high speed visualization and for the other a fiber optic probe hydrophone (FOPH) pressure transducer was used. In using the former way, propagation of underwater shock waves and behavior of the bubble near the electrodes were studied, and the velocities and pressures of underwater shock waves were calculated. In using the later method, two kinds of underwater shock waves pressures were measured at a 5 mm to 10 mm distant from the electrodes. To analyze these underwater shock waves near the electrodes by high speed visualization, a cylindrical test section was used. The underwater shock waves with the parameters determined based on the result of above analysis were applied in-vivo to cultured cancer cells.