title: 2-D mapping of skin chromophores in the spectral range 500 - 700 nm.
abstract: The multi-spectral imaging technique has been used for distant mapping of in-vivo skin chromophores by analyzing spectral data at each reflected image pixel and constructing 2-D maps of the relative concentrations of oxy-/deoxy-haemoglobin and melanin. Instead of using a broad visible-NIR spectral range, this study focuses on narrowed spectral band 500-700 nm, speeding-up the signal processing procedure. Regression analysis confirmed that superposition of three Gaussians is optimal analytic approximation for the oxy-haemoglobin absorption tabular spectrum in this spectral band, while superposition of two Gaussians fits well for deoxy-haemoglobin absorption and exponential function - for melanin absorption. The proposed approach was clinically tested for three types of in-vivo skin provocations: ultraviolet irradiance, chemical reaction with vinegar essence and finger arterial occlusion. Spectral range 500-700 nm provided better sensitivity to oxy-haemoglobin changes and higher response stability to melanin than two reduced ranges 500-600 nm and 530-620 nm.
authors.affiliation: Bio-Optics and Fibre Optics Laboratory, Institute of Atomic Physics and Spectroscopy, University of Latvia, Raina Blvd. 19, LV - 1586, Riga, Latvia. dainis.jakovels@gmail.com
authors.forename: Dainis
authors.initials: D
authors.lastname: Jakovels
authors.forename: Janis
authors.initials: J
authors.lastname: Spigulis
mesh_terms: D005385:Fingers / Q000098:blood supply / Q000502:physiology / Q000528:radiation effects; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D016018:Least-Squares Analysis; D008027:Light; D008543:Melanins / Q000737:chemistry* / Q000378:metabolism / Q000528:radiation effects*; D010108:Oxyhemoglobins / Q000378:metabolism; D012867:Skin / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D012880:Skin Pigmentation / Q000502:physiology / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D006454:Hemoglobins; D008543:Melanins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin