Spectral properties of cancerous and normal human breast and lung tissues

Transient state, excitation spectra, and time- resolved spectroscopic dynamics from normal and cancerous human breast and lung tissues have been studied and are presented. The spectral profiles obtained from samples excited with the second and third harmonic of a picosecond pulse Nd:glass laser were different for normal and cancerous tissues. The main peaks at ~450 nm were shifted, while the subsidiary peaks of normal tissues smoothed out in the cancerous tissues with less structure. The excitation spectra for the three different emission wavelengths at 520, 550, and 600 nm corresponding to the three peaks in the normal tissue fluorescence spectra were measured. The overall excitation spectra showed broad UV and visible bands with differences between the cancerous and normal tissues. The dynamic profiles of the fluorescence spectra were measured using photoexcitation by 350- and 530 nm light from a picosecond pulse Nd:glass laser and a streak camera detection system. The kinetic profiles showed faster decay times for the cancerous tissues compared with normal tissues. The spectroscopic differences were attributed to changes in flavins, porphyrins, and the surrounding media.