title: Monte Carlo model to describe depth selective fluorescence spectra of epithelial tissue: applications for diagnosis of oral precancer.
abstract: We present a Monte Carlo model to predict fluorescence spectra of the oral mucosa obtained with a depth-selective fiber optic probe as a function of tissue optical properties. A model sensitivity analysis determines how variations in optical parameters associated with neoplastic development influence the intensity and shape of spectra, and elucidates the biological basis for differences in spectra from normal and premalignant oral sites. Predictions indicate that spectra of oral mucosa collected with a depth-selective probe are affected by variations in epithelial optical properties, and to a lesser extent, by changes in superficial stromal parameters, but not by changes in the optical properties of deeper stroma. The depth selective probe offers enhanced detection of epithelial fluorescence, with 90% of the detected signal originating from the epithelium and superficial stroma. Predicted depth-selective spectra are in good agreement with measured average spectra from normal and dysplastic oral sites. Changes in parameters associated with dysplastic progression lead to a decreased fluorescence intensity and a shift of the spectra to longer emission wavelengths. Decreased fluorescence is due to a drop in detected stromal photons, whereas the shift of spectral shape is attributed to an increased fraction of detected photons arising in the epithelium.
authors.affiliation: Cornell University, School of Applied and Engineering Physics, Ithaca, New York 14853, USA.
authors.forename: Ina
authors.initials: I
authors.lastname: Pavlova
authors.forename: Crystal Redden
authors.initials: CR
authors.lastname: Weber
authors.forename: Richard A
authors.initials: RA
authors.lastname: Schwarz
authors.forename: Michelle
authors.initials: M
authors.lastname: Williams
authors.forename: Adel
authors.initials: A
authors.lastname: El-Naggar
authors.forename: Ann
authors.initials: A
authors.lastname: Gillenwater
authors.forename: Rebecca
authors.initials: R
authors.lastname: Richards-Kortum
mesh_terms: D003198:Computer Simulation; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008856:Microscopy, Fluorescence / Q000295:instrumentation / Q000379:methods*; D008954:Models, Biological; D015233:Models, Statistical; D009010:Monte Carlo Method; D009061:Mouth Mucosa / Q000473:pathology*; D009062:Mouth Neoplasms / Q000175:diagnosis*; D019047:Phantoms, Imaging; D011230:Precancerous Conditions / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*