Abstract: A method for inactivating ocular viral pathogens and for treating associated lesions on tissue by means of selectively activating a tissue-associated photosensitizing agent with light. The photosensitizing agent, preferably tin ethyl etiopurpurin, is administered to a patient to concentrate within the lesionous target tissue of the eye. The photosensitizer-laden target tissue is irradiated with photoactivating light. In pre-clinical in vitro studies, the photoactivated photosensitizer drug within the lesionous target tissue inactivates both cell free Herpes simplex virus (HSV) and cell-associated HSV and cytomegalovirus (CMV). The use of PDT for treating ocular viral diseases reduces the toxicity to the biological system when compared with prior art therapeutic procedures.

Abstract: The present invention is an improved balloon-type catheter with an integral fiber optic assembly for delivering light to a intraluminal target wherein the improvement comprises the use of a perfusion channel to bypass the balloon near the tip of the catheter. The bypass channel enables a fluid material such as oxygen or blood to flow around the inflated balloon during photo-irradiation. A preferred embodiment of the balloon-type perfusion includes a body portion comprising an elongated, flexible, tubular sheath having proximal and distal ends. The body portion is internally partitioned into three longitudinal lumens. The first lumen contains the illuminating fiber optics that include a cylindrical light diffuser tip. The second lumen is an inflation passage for conducting inflation fluid to a balloon which coaxially surrounds the sheath overlying the diffuser tip terminus of the fiber optics near the distal end of the catheter.

Abstract: A light delivery device including an interchangeable handpiece and a semiconductor light source module adapted to releasably attach to the handpiece. The light source module includes a two-dimensional array of light emitting diodes (LED's) disposed on a surface of a fluid-cooled electrically conductive support plate. The device is adapted for uniformly illuminating a tissue surface with phototherapeutic light. The phototherapeutic light is produced by an array of over-driven LED's mounted on the surface of the heat-sinked support. The semiconductor light source employs a multi-layer construction wherein electrically conductive layers are thermally isolated from each other. The device is rugged, inexpensive and can produce high optical power while operating at a temperature well below the temperature at which device failure occurs. The light source module is adapted to be releasably connected to an interchangeable LED handpiece which provides power to the LED's and conducts a coolant fluid.

Abstract: An apparatus for detecting the presence of cancerous tissue using fluorescence. The apparatus employs an external light source capable of delivering about 50 milliwatts of excitation power within the absorption spectrum of tumor-specific target fluorescent molecules. Excitation light enters the fluorescent probe where it is chopped and divided, a portion being transmitted through an optical fiber to endogenous or exogenous photosensitive molecules on the surface of the tumor. The photosensitive molecules, once excited, generate a fluorescence spectrum characteristic of the cell type. The fluorescence emitted from the excited photoactive molecules on the tumor enters the optical fiber and passes to the fluorescence probe where it is filtered and analyzed. The use of the single fiber for both excitation and detection of fluorescence light enables the probe to be inserted into extremely small openings.

Abstract: This invention describes a method for the accurate and sensitive measurement of an exogenous fluorescence chromophore in vivo. The method provides a means for normalizing a typical endogenous fluorescence signal into a relatively narrow band of values for different tissue types. The method employs irradiation of a target tissue at a single excitation wavelength while measuring two narrow bands of emission wavelengths, one of which is principally associated with the endogenous autofluorescence of the tissue while the other is chosen to be characteristic of the exogenous chromophore of interest. An exogenous chromophore is administered to a target tissue in vivo. A fiber optic positioned near the target tissue delivers illuminating excitation light from a light source to the tissue and receives fluorescence light from both exogenous and endogenous chromophores in the tissue and conducts the fluorescence light to a detector.

Abstract: A device for measuring the fluorescence generated by photoactivated molecules during photodynamic therapy (PDT) and a method of using the device for dosimetry. The device, which comprises an isotropic spherical probe and detector electronics, simultaneously measures the space irradiance and time-integrated fluorescence during PDT. It is shown that there is a correlation between the time-integrated fluorescence generated during PDT treatment of a tumor and the delay in the regrowth of the tumor. The device provides the simultaneous measurement of the space irradiance and integrated fluorescence which measurements enable real time dosimetry during PDT.

Abstract: A steerable catheter is disclosed which can treat luminal surfaces such as those occurring in the vascular tree, pulmonary tree, gastrointestinal tract, urological organs, etc. with Photodynamic Therapy (PDT) or other optical diffusing treatments. The catheter, which may include an inflatable balloon portion, has a light diffusing tip which can be deflected allowing the catheter to be steered precisely. The light diffusing tip on the steerable catheter is able to gain access to and enter virtually any sub-branch of the luminal system being treated. Since this catheter does not require a guidewire lumen for insertion, the profile is reduced. A low profile device allows treatment light to be delivered to the walls of the most distal, small diameter lumen.

Abstract: Following recanalization of a stenotic blood vessel, a photosensitizer is administered by means of a vaso-absorbable stent to maintain the photosensitizer concentration level in the atheromatous plaque and smooth muscle cells in the vicinity of the lesion for a period of 5-18 days, the period in which cell proliferation can occur. The Vaso-Absorbable Stent (VAST) is described along with the method for its use in Photoatherolytic (PAL) Therapy. The VAST device is used post cardiovascular intervention to: a) deliver a series of drugs to prevent cell proliferation leading to restenosis; and, (b) maintain the patency of the treated vessel and prevent elastic recoil of the vessel by providing support for the vessel wall; and c) deliver and maintain a level of photosensitizer to the treatment site which inhibits smooth muscle cell proliferation and, when activated by light energy, induces cell lysis.

Abstract: A cylindrical diffuser tip for use with an optical fiber is described. The diffuser tip comprises a silicone core abutted to the terminus of the conventional optical core of an optical fiber, an outer layer of silicone plus a suitable scatterer, and a final cladding of plastic tubing to provide controlled stiffness or rigidity to the silicone diffuser tip while maintaining a flexibility comparable to the optical fiber. The tip provides a substantially uniform distribution of radiance along its length and is particularly useful for laser radiation treatment of tumors. The stiffness of the diffuser tip can be varied by choosing an outer tubing of varying wall thickness and durometer. The diffuser tip is useful for providing uniform cylindrical illumination of target tissue in remote areas of the body and is particularly useful in such areas as Photodynamic Therapy of tumors and atheromas and hyperthermia.

Abstract: An improved power meter for measuring the energy and wavelength of light emanating from an optical fiber. The meter is an integrating sphere having a source aperture for receiving the tip of an optical fiber and coupling the light from the tip into the sphere's central cavity. The source aperture is modified to include a sterilizable, liquid-fillable insert which mimics the optical environment within tissue. The sphere also has improved baffling and the sensitivity of wavelength verification is improved by means of a rotatable interference filter placed between an exit aperture and a light detector.

Abstract: A cylindrical diffuser tip for use with an optical fiber is described. The diffuser tip comprises a silicone core containing scattering centers embedded therein abutted to the terminus of the conventional optical core of an optical fiber, and an outer protective plastic tube to provide controlled stiffness or rigidity to the silicone diffuser tip while maintaining a flexibility comparable to that of the optical fiber. The scattering centers embedded in the silicone core are distributed to provide a gradient that increases continuously in a direction perpendicular from the terminus face of the optical fiber. The tip provides a substantially uniform distribution of radiance along its length and is particularly useful for laser radiation treatment of tumors. The stiffness of the diffuser tip can be varied by choosing a protective tube of varying wall thickness and durometer.