title: In vivo time-resolved spectroscopy of the human bronchial early cancer autofluorescence.
abstract: Time-resolved measurements of tissue autofluorescence (AF) excited at 405 nm were carried out with an optical-fiber-based spectrometer in the bronchi of 11 patients. The objectives consisted of assessing the lifetime as a new tumor/normal (T/N) tissue contrast parameter and trying to explain the origin of the contrasts observed when using AF-based cancer detection imaging systems. No significant change in the AF lifetimes was found. AF bronchoscopy performed in parallel with an imaging device revealed both intensity and spectral contrasts. Our results suggest that the spectral contrast might be due to an enhanced blood concentration just below the epithelial layers of the lesion. The intensity contrast probably results from the thickening of the epithelium in the lesions. The absence of T/N lifetime contrast indicates that the quenching is not at the origin of the fluorescence intensity and spectral contrasts. These lifetimes (6.9 ns, 2.0 ns, and 0.2 ns) were consistent for all the examined sites. The fact that these lifetimes are the same for different emission domains ranging between 430 and 680 nm indicates that there is probably only one dominant fluorophore involved. The measured lifetimes suggest that this fluorophore is elastin.
authors.affiliation: Swiss Federal Institute of Technology in Lausanne (EPFL), Institute of Chemical Sciences and Engineering, Station 6, CH-1015 Lausanne, Switzerland.
authors.forename: Pascal
authors.initials: P
authors.lastname: Uehlinger
authors.forename: Tanja
authors.initials: T
authors.lastname: Gabrecht
authors.forename: Thomas
authors.initials: T
authors.lastname: Glanzmann
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Ballini
authors.forename: Alexandre
authors.initials: A
authors.lastname: Radu
authors.forename: Snezana
authors.initials: S
authors.lastname: Andrejevic
authors.forename: Philippe
authors.initials: P
authors.lastname: Monnier
authors.forename: Georges
authors.initials: G
authors.lastname: Wagnières
mesh_terms: D000465:Algorithms; D014408:Biomarkers, Tumor / Q000032:analysis*; D001984:Bronchial Neoplasms / Q000737:chemistry* / Q000175:diagnosis*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D006801:Humans; D009363:Neoplasm Proteins / Q000032:analysis*; D011230:Precancerous Conditions / Q000737:chemistry / Q000175:diagnosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins