FIBER-DELIVERED ERBIUM: YAG LASER FOR ANGIOPLASTY

A COMMERCIAL MODEL OF AN OPTICALLY PUMPED, PULSED, ER:YAG SOLID-STATE LASER WILL BE MODIFIED AND TESTED FOR BEAM PERFORMANCE AND USED IN CONJUNCTION WITH A COMPATIBLE LOW-LOSS, FLEXIBLE NONTOXIC, FLUORIDE GLASS DELIVERY FIBER TO STUDY IN VITRO TUSSUE INTERACTION EFFECTS. THE LASER OPERATES AT AN APPROXIMATE WAVELENGTH OF 2.94 MUM ON THE 4I11/2-4I13/2 TRANSITION OF TRIVALENT ERBIUM. TISSUE INTERACTION STUDIES AT THIS WAVE-LENGTH, WHICH FALLS AT THE PEAK OF THE STRONG INFRA-RED-ABSORPTION BAND OF WATER, HAVE DEMONSTRATED EFFICIENT, ABLATIVE-TYPE CUTTING WITH MINIMAL THERMAL DAMAGE TO SURROUNDING AREAS. OPTIMIZATION AND REFINEMENT OF THE LASER-TISSUE INTERACTION, IN PARTICULAR AS A FUNCTION OF PULSE ENERGY AND TEMPORAL PROFILE, ARE NOW REQUIRED. INITIAL, DIRECT-FOCUSED BEAM EXPERIMENTS ARE PROPOSED, TO BE FOLLOWED BY TESTING OF COMMERCIALLY AVAILABLE ZIRCONIUM-FLUORIDE GLASS FIBERS FOR LASER DAMAGE AND FOR EFFICACY IN CONTACT TISSUE MACHINING IN VITRO IN A WET FIELD. FAVORABLE RESULTS WILL QUALIFY THE SYSTEM FOR ENDOSCOPIC APPLICATIONS IN GENERAL LASER SURGERY AND, IN PARTICULAR, FOR CATHETER-GUIDED ANGIOPLASTY IN PERIPHERAL AND CORONARY VESSELS. THE EXACTING REQUIREMENTS FOR REMOVAL OF PLAQUE INTHESE LATTER APPLICATIONS DEMAND PRECISION CUTTING, AND THE ER:YAG LASER WOULD APPEAR TO BE UNIQUE IN ITS ABILITY TO PROVIDE THIS INTERACTION VIA A FLEXIBLE FIBER.