Apparatus for detecting the presence of abnormal tissue within a target

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. 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.