Abstract: Laser-induced fluorescence spectra of normal mucosa and adenocarcinomatous of human colon tissues were investigated using excitation wavelengths of 457.9, 488, 514.5 and 632.8 nm respectively. The characteristic spectral differences between normal and adenocarcinomatous tissues had been observed at the wavelengths greater than 600 nm. In addition, emission intensities at 580 and 720 nm versus laser irradiation time were measured in both normal and abnormal tissues. Non-linear regression fitting of the obtained autofluorescence decay profiles illustrated that the autofluorescence decay followed a double exponential behavior. The evaluation of temporal dynamics of the autofluorescence processes may reveal the different accumulated concentration of endogenous fluorophores between normal and tumor tissues. Furthermore, the fluorescence intensity of the normal and tumor colonic tissues as a function of tissue thickness was also studied. The best fit to the data can yield the effective optical attenuation coefficients of human colon tissues. !20
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