Compact multi-functional skin spectrometry set-up

A portable fibre-optic spectrometry set-up has been assembled and tested for applications in skin diffuse reflectance spectrometry, laser fluorescence spectrometry and multi-wavelength reflection photoplethysmography (multi-PPG) studies. The spectrometry set was tested by diffuse reflectance and fluorescence measurements for diagnostics of skin vascular malformations and pigmented diseases such as nevi and melanoma. In addition, studies of microcirculation in blood vessels located at different depths from the skin surface were performed by the multi-PPG method. The results of skin diffuse reflectance and autofluorescence showed differences in spectra of healthy and pathologic skin. The parameter ratio "pathologic/healthy" has been calculated in order to check the possibility of quantifying the specific pathology. The autofluorescence fading effect was observed. Our studies of the blood volume pulsations confirmed the possibility to separate the time-variable PPG component from the total skin diffuse reflectance signal.