Pigmented skin lesions by VIS-NIR reflectance spectroscopy

The increase in the incidence of pigmented skin lesions in the last decade together with the fact that early detection could allow a mortality reduction has lead to the development of spectrometric diagnostic techniques applicable to dermatology. These techniques are based on the evidence that the presence of malignant cells should somehow alter the optical characteristics of epidermis with respect to the healthy one and a different reflectance spectrum should appear. The subjectivity of the clinical observation by the specialist is, in this way, substituted by an objective technique, with the improve of the specificity and the sensitivity. The aim of this work is to obtain a skin reflectance database of both benign and malignant lesions as well as of healthy skin which permits to establish algorithms and discrimination rules for a more objective identification of different pigmented skin lesions. The measure system consists of a portable visible near infrared (600-1000 nm) spectrometer (AVS-USB200, Avantes), a tungsten halogen lamp (HL-200) and fiber optics reflection probes. The parameters of that system and their variability has been tested in steady state conditions by using neutral filters and a white reference tile. A reproducibility study of both normal and pigmented skin diffuse reflectance spectra has been carried out. After that a small scale study of selected subjects have been conducted. This study has comprised the collection of spectra from different skin pigmented lesions and the clinical evaluation of its lesions characteristics by the dermatologist. The results after the analysis of the collected data are presented.