Autofluorescence and diffuse reflectance spectroscopy of pigment disorders in human skin

• Published in: Journal of Optoelectronics and Advanced Materials 2008-03, Vol.10 (3), p.717-722
• Main Authors: Borisova, E G, Nikolova, E, Troyanova, P P, Avramov, L A
• Format: Article
• Language: English
• ISSN: 1454-4164

Many up-to-date techniques based on recent progress in optics have been developed for medical applications. Fluorescence, absorption, and reflectance spectroscopy have been widely used as probes to acquire fundamental knowledge about physical, chemical, and biological processes. In the recent years, there has been growing interest in the common use of laser-induced autofluorescence (LIAF) and reflectance spectroscopy (RS) to differentiate disease from normal surrounding tissue - so called optical biopsy method. The goals of this work were investigation of cutaneous benign and malignant lesions by the methods of LIAFS and RS. A nitrogen laser at 337 nm was applied for the needs of autofluorescence excitation. Broad-spectrum halogen lamp (from 400 to 900 nm) was applied for diffuse reflectance measurements. An associated microspectrometer detected in vivo the fluorescence and reflectance signals from human skin. The main spectral features of benign lesions - compound nevus, dysplastic nevi and malignant lesions - pigmented, amelanotic and secondary malignant melanoma are discussed and their possible origins are indicated. Spectra from healthy skin areas near to the lesion were detected to be used posteriori to reveal changes between healthy and lesion skin spectra. Influence of the main skin pigments on the spectra detected is discussed and evaluation of possibilities for differentiation between malignant and benign lesions is made based on their spectral properties. This research shows that non-invasive and high-sensitive in vivo detection by means of appropriate light sources and detectors should be possible, related to real-time determination of existing pathological conditions.