Abstract: A shielded tip catheter for use with a pulsed energy source for fracturing deposits such as urinary and biliary stones and atherosclerotic plaque in the human body is disclosed. The flexible catheter has a shielded tip structure which is adapted for insertion through a fluid passage in a living body. The tip structure can contain an impact element, a scraping implement or a cutting implement. An energy source creates repeated rapid vapor expansions adjacent the element causing it to undergo repeated pulse like movements, imparting a series of high-velocity impulses to an adjacent deposit, thereby fracturing or cutting it. The energy source can be a laser with a fiber optic delivery system in the catheter terminating adjacent the impact element, or a spark generator with a conductor within the catheter to deliver a fluid vaporizing spark adjacent the element.