A computerized autofluorescence and diffuse reflectance spectroanalyser system for in vivo skin studies

A microcomputer-controlled spectroanalyser system has been set up to study optical properties of normal and abnormal human skin in vivo. The system can measure both tissue autofluorescence and diffuse reflectance at selected skin locations. The sample holder allows adjustment of the incident angle of the illumination light and the pick-up angle of the collected light providing the means to examine different depths of skin tissue. Using this system, we detected measurable skin autofluorescence with a maximum at about 470 nm when excited with 380 nm UV radiation. In this work, we also show that the absorption and scattering properties of the skin tissue (which can be determined from the measured diffuse reflectance spectrum) affect the shape of the autofluorescence spectrum. We believe that the combination of autofluorescence and diffuse reflectance measurements will lead to better understanding of the optical properties of normal and abnormal skin tissue.