Abstract: A method in which photodynamic therapy is employed to inhibit, stabilize or reduce occlusions within the cardiovascular system by utilizing light within the spectral region of approximately 390 to approximately 610 nm.

Abstract: An optical light diffuser providing a generally cylindrical pattern of light emission. The diffuser is formed from an optical fiber operable to transmit the optical radiation from its proximal end to its distal end and having a guiding core and a cladding surrounding the core. The optical fiber has an abraded section at its distal end that allows light to escape uniformly over the abraded section forming a generally cylindrical pattern of diffuse light that surrounds the distal end of the optical fiber.

Abstract: A method for intraoperatively administering Photodynamic Therapy (PDT) to a highly vascularized target tissue. The method of PDT begins with the introduction of an exogenous photosensitizing agent into the target tissue-associated vasculature. Upon entry of the photosensitizer into the vasculature, the target tissue is immediately exposed to phototherapeutic light having a wavelength suitable for photoactivating the photosensitizer within the target tissue-associated vasculature. Continued illumination of the target tissue affects destruction of the vasculature within the tissue without requiring the photosensitizer to accumulate within the nonvascular tissue cells prior to photoactivation. The destruction of the vasculature supplying the target tissue destroys the target tissue. The method eliminates the prior art procedural step of waiting for the photosensitive compound to accumulate within the target tissue cells prior to administering photoactivating light to the target tissue.

Abstract: A light diffuser tip for use with an optical fiber. The diffuser tip is affixed to an optical fiber and comprises an optically transparent elastomer core positioned to receive light from the output terminus of the optical fiber. The concentration of scattering centers embedded in the transparent elastomer core varies along the length of the core to yield a particular light distribution pattern. For example, the scattering centers may be distributed within an optically transparent elastomeric core material such as silicone to provide a scatterer density gradient along the diffuser tip in the axial direction of the optical fiber. A diffuser tip which provides uniform cylindrical light output intensity in air will provide a different output intensity distribution in a medium with a different index of refraction such as human tissue.

Abstract: A catheter and a method for using the catheter for the transluminal hyperthermic treatment of target tissue is presented. The catheter comprises an elongate tubular member having two coolant circulating lumens and an optical waveguide coextensive therewith, the proximal end of the optical waveguide being adapted to receive light from a light source and the distal end of the optical waveguide terminating in a diffuser tip. The diffuser tip provides a means for radially distributing treatment light from the light source to tissue adjacent to the distal tip of the catheter to heat the tissue. A transparent, inflatable balloon surrounds the diffuser tip. The inflatable balloon permits the flow of an optically transparent coolant around the diffuser tip to cool the tissue immediately adjacent to the diffuser tip to prevent overheating. A method of using the device for the transurethral treatment of benign prostate hypertrophy is presented as an example.

Abstract: A device for delivering phototherapeutic light to uniformly illuminate a tissue surface. The device is a bowl-shaped shell with a more-or-less parabolic profile and having an open end and an apex. The inner surface of the shell is adapted to diffusely reflect light with very low absorption by the shell material. A light output end of a fiber optic is introduced into the interior of the shell through a fiber optic port in the shell wall near the apex. The light output end of the fiber is positioned such that light emanating therefrom impinges upon the inner surface of the shell. The shape of the shell causes greater than 60 percent of the light emanating from the fiber to intercept the shell's surface and be diffusely reflected. The diffusely reflected light may then undergo further diffuse reflection within the shell prior to reaching the treatment surface adjacent to the open end of the shell to provide more uniform illumination of the treatment surface than the fiber could otherwise provide.

Abstract: A microlens tip assembly for focusing output light from a light delivery catheter upon a target tissue. Due to the inherent divergence of output light from diode lasers, when such divergent light is conducted from the proximal end of a catheter to the distal end by means of a fiber optic, a portion is reflected at the fiber/air/lens interface to impinge upon the microlens housing area thereby heating the housing assembly resulting in overheating at high power levels and possible device failure and/or tissue damage. The present high-powered microlens includes a rear and front mount, both of which are fabricated from a non-light-absorbing material such as transparent or white plastic. The use of transparent or non-ligh-absorbing plastic components decreases the amount of heating of the tip assembly during light delivery, thereby solving the problem of therapeutic light delivery device failures and/or tissue damage due to overheating.

Abstract: A light delivery catheter having an elongate, flexible inner tube coaxially disposed within a lumen within a flexible outer tube, and axially movable with respect to the outer tube. An optical waveguide disposed within the inner tube conducts light from an external light source to a light diffuser element in optical communication with the distal end of the optical waveguide. A portion of the light conducted to the diffuser element is scattered radially into the surrounding volume. The outer diameter of the inner tube is less than the diameter of the outer tube lumen, the annular space therebetween forming a cylindrical lumen coextensive with the inner tube. One or more fiber optics disposed within the cylindrical lumen are attached to the outer surface of the inner tube and terminate distally in an isotropic tip.