Pdt Systems, LLC

A Charles Lytle

Daniel R Doiron

Gregory S Graham

John B Dunn

Brian K Dalton

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. The light source includes an integral unitary reflector for directing the light output from the individual LED's in the LED array in a desired direction. The reflector is a thin perforated sheet having a top, tissue facing surface and bottom surface and an array of cup shaped openings therebetween, each such perforation in the sheet being disposed to overly a LED in the LED array. The inner surface of each cup-shaped opening has a parabolic vertical cross section and is reflectively coated to maximize red reflectivity.

Uniform illuminator for phototherapy

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. The fluorescence probe will measure the magnitude of excitation light delivered and reflected from the tissue thereby giving a quantitative measurement of the fiber tip-to-tissue distance and tissue optical characteristics. The apparatus also can distinguish variations in fluorescence due to differences in distance of the fiber tip from the tissue under investigation by measuring the ratio of fluorescence and/or reflectance at two different wavelengths.

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Nipomo, CA, United States of America

A Charles Lytle