Abstract: The present invention provides improved methods and devices for delivering light to the surface of a biological column, for example in the treatment of Barrett's esophagus using PDT. The improvement comprises the use of an extended irradiation segment or window. The improved methods of the present invention permits treatment lengths of the biological column to be increased without increasing the incidence of stricture formation.

Abstract: An apparatus and method for cancer diagnosis are disclosed. The diagnostic method includes the steps of irradiating a tissue sample with monochromatic excitation light, producing a laser-induced fluorescence spectrum from emission radiation generated by interaction of the excitation light with the tissue sample, and dividing the intensity at each wavelength of the laser-induced fluorescence spectrum by the integrated area under the laser-induced fluorescence spectrum to produce a normalized spectrum. A mathematical difference between the normalized spectrum and an average value of a reference set of normalized spectra which correspond to normal tissues is calculated, which provides for amplifying small changes in weak signals from malignant tissues for improved analysis. The calculated differential normalized spectrum is correlated to a specific condition of a tissue sample.