Abstract: Methods and devices are disclosed in which a dielectric structure is operatively coupled to phototherapeutic instrument to reflect light without substantial heating. The invention is particularly useful in light diffusive tip assemblies for phototherapy that have components which increase in temperature after prolonged exposure to light, such as metallic plugs or coatings typically located at the end cap of the diffusive tip assembly to terminate light propagation, and also metallic structures incorporated into phototherapeutic instruments to facilitate radiographic or fluoroscopic imaging during a therapeutic procedure.

Abstract: An optical transmissive fiber tip assembly having a radiation-scattering particles incorporated therein and a reflective end surface is disclosed for use in phototherapy. As radiation propagates through the fiber tip, a portion of the radiation is scattered in a cylindrical (or partially cylindrical) pattern along the length of the fiber tip. Radiation which is not scattered during this initial pass through the tip is reflected by at least one surface of the assembly and returned through the tip. During this second pass, the remaining radiation (or at least a major portion of this returning radiation) again encounters the scatterers which provide further radial diffusion of the radiation. In one embodiment, a diffusive tip assembly is disclosed for diffusing radiation from an optical fiber. The tip assembly is adapted to receive the distal end of said fiber in order to direct the radiation outward, and includes a light transmissive tube or housing aligned with the distal end of the fiber.

Abstract: Laser energy produced by a laser operating in the mid-infrared region (approximately 2 micrometers) is delivered by an optical fiber in a catheter to a surgical site for biological tissue removal and repair. Disclosed laser sources which have an output wavelength in this region include: Holmium-doped Yttrium Aluminum Garnet (Ho:YAG), Holmium-doped Yttrium Lithium Fluoride (Ho:YLF), Erbium-doped YAG, Erbium-doped YLF and Thulium-doped YAG. For tissue removal, the lasers are operated with relatively long pulses at energy levels of approximately 1 joule per pulse. For tissue repair, the lasers are operated in a continuous wave mode at low power. Laser output energy is applied to a silica-based optical fiber which has been specially purified to reduce the hydroxyl-ion concentration to a low level. The catheter may be comprised of a single optical fiber or a plurality of optical fibers arranged to give overlapping output patterns for large area coverage.

Abstract: Methods and devices for practicing fluorescence spectroscopy to detect abnormal or cancerous tissue employing an transparent fluoropolymer optical probe to irradiate a target region of biological material and measure the fluorescent response of the target tissue. Based on the spectral response of the target region, the presence (or absence) of abnormal tissue can be determined. Transparent fluoropolymers reduce background fluorescence, thereby improving the signal-to-noise ratio in spectral analysis, because fluoropolymers have low self-fluorescence and, therefore, do not respond to ultraviolet excitation radiation with significant fluorescence of their own that would otherwise mask or interfere with the fluorescent radiation collected from a target tissue region in response to UV excitation radiation.

Abstract: Methods and systems for endoscopic suturing of biological tissue are disclosed. Endoscopic instruments are described which serve to position a suture material at an anastomotic site and deliver laser radiation to the suture material to effect fusion. The suture material includes a structure adapted for positioning at an anastomotic site and has at least a portion of the structure formed by a photoreactive crosslinking agent, such that upon irradiation of the structure the crosslinking agent adheres to the biological material. In one embodiment, the suture material can also include a high tensile strength element which is coated with a laser activatable crosslinking agent or glue. Upon activation, the suture material creates a desired closure or joinder of the biological material and is left in place while the endoscope is advanced to another target site or removed.

Abstract: Phototherapeutic instruments are disclosed having integral stopper devices which limit the penetration of an optical fiber during tissue penetrating phototherapy. In one preferred embodiment, a fluted outer sheath is disposed about an internal optical fiber. The fluted sheath is configured to expand during penetration of the optical fiber into a patient's tissue. As the fluted elements expand, the present a much larger cross-sectional area which resists further penetration of the instrument beyond a predetermined desirable distance. The invention is useful in limiting an optically-transmissive fiber's penetration and, thereby, reduce the possibility of perforation of a body lumen or organ. The invention is particularly useful in placing a ablative laser radiation device into the ventricle of the heart when performing arrhythmia-correcting laser ablative procedures or when revascularizing the heart percutaneously.

Abstract: Methods and devices are disclosed for sterilization of endoscopic instrument lumens. Diffuse ultraviolet radiation is employed to sterilize the inner surfaces of the instrument lumen. The ultraviolet radiation can be delivered via one or more optical fibers having a light-diffusing assembly coupled thereto. The instrument operates by delivering cytotoxic radiation to the inner lumen surface to sterilize any biological agents which may be present within the instrument lumen.

Abstract: Methods and apparatus are disclosed for diffusing radiation from a optical fiber to provide a larger exposure area for phototherapy and to provide a substantially uniform energy distribution to a major portion of the exposure area. The invention is especially useful in constructing and implementing circumferential and/or sideways-emitting diffusive tip assemblies, or quasi-spherical diffusive tip assemblies for optical fibers to direct laser radiation in a radially outward pattern relative to the fiber's axis. In one aspect of the invention, a plurality of optically-transmissive fiber tip assemblies are employed to act as diffusers. The two or more fiber tip assemblies are deployed as loops which create a uniform illumination pattern. By "looping" or "folding" the fibers, a plurality of fibers can be deployed in conjunction with one another to create geometric exposure patterns with increased energy density while still avoiding "hot spots.

Abstract: Materials and methods for photoreactive suturing of biological tissue are disclosed. The suture material includes a structure adapted for positioning at an anastomotic site and has at least a portion of the structure formed by a photoreactive crosslinking agent, such that upon irradiation of the structure the crosslinking agent adheres to the biological material. In one embodiment, the suture material can also include a high tensile strength element which is coated with a laser activatable crosslinking agent or glue. The suture methods can be practiced manually, or with various apparatus, such as endoscopes, catheters or hand-held instruments.

Abstract: Methods and systems for endoscopic suturing of biological tissue are disclosed. Endoscopic instruments are described which serve to position a suture material at an anastomotic site and deliver laser radiation to the suture material to effect fusion. The suture material includes a structure adapted for positioning at an anastomotic site and has at least a portion of the structure formed by a photoreactive crosslinking agent, such that upon irradiation of the structure the crosslinking agent adheres to the biological material. In one embodiment, the suture material can also include a high tensile strength element which is coated with a laser activatable crosslinking agent or glue. Upon activation, the suture material creates a desired closure or joinder of the biological material and is left in place while the endoscope is advanced to another target site or removed.

Abstract: A variable pulsewidth laser system is disclosed which employs an oscillating reflector to control the duration of laser pulses. In one embodiment, the oscillating mirror is swept (e.g., caused to swing back and forth) about an axis distinct from the optical axis, such that resonant conditions suitable for laser beam generation occur only at a particular location in the oscillating sweep path. By varying the scanning waveform, laser pulses of different durations can be generated.

Abstract: Materials and methods for photoreactive suturing of biological tissue are disclosed. The suture material includes a structure adapted for positioning at an anastomotic site and has at least a portion of the structure formed by a photoreactive crosslinking agent, such that upon irradiation of the structure the crosslinking agent adheres to the biological material. In one embodiment, the suture material can also include a high tensile strength element which is coated with a laser activatable crosslinking agent or glue. The suture methods can be practiced manually, or with various apparatus, such as endoscopes, catheters or hand-held instruments.