New lasers, delivery systems, and photo-sensitizers have broadened horizons in the field of photo-medicine. The tissue's response is highly influenced by its optical properties as well as the geometry of the incident beam. Sometimes modification of the profile of the beam to match the volume of tissue involvement during procedure such as photodynamic and photothermal therapy is desired. Recently interest has developed in fiberoptics for contact surgery and uniform irradiation of tissue during photodynamic therapy. More recently, side emitting tips have been developed for directional irradiation during photothermal therapy. These tips are designed to reflect the laser beam at a 90 degree angle. If a large surface of tissue needs to be irradiated, one must position the tip with multiple laser exposure, aimed only at the untreated areas. Other diffusing tips have not been optimized for the delivery of tens of watts needed for coagulating large volumes. REM seeks to further develop a family of diffusing tips for directional and non-directional, isotropic distribution of laser light.It is proposed to optimize diffusing tips at 630 nm for PDT therapy, 800 and 940 nm light from laser diodes, and l.06um for photocoagulation therapy. These tips will be characterized in air, phantom media, and tissue samples to evaluate and optimize their performance.
