<title>Biochemical distinctions between normal and cancerous human breast tissues obtained from fluorescence spectroscopy</title>

Abstract

A novel method for correcting the fluorescence emission and excitation spectra is applied to native fluorescence spectra from normal and cancerous human breast tissues. The method effectively eliminates the distortions produced by internal light-absorption and allows a direct, real-time, correction without any iterative procedures. A simplified photon- diffusion model was used to develop the method. An analysis of both the true fluorescence spectra, and the diffuse reflectance spectra transformed into the ratio of absorption and reduced scattering coefficients, shows distinctive biochemical differences between cancerous and normal breast tissues. The fluorescence spectra feature a lower contribution of NADH and, possibly, collagen and elastin in cancerous tumor tissues as compared with normal tissues. The fluorescence spectra from cancerous tumors also show a lower degree of variability than the spectra from normal tissues. The corrected spectra from cancerous tumors show a greater similarity in their profiles than the non-corrected fluorescence spectra distorted by the internal light- absorption.