Double-wavelength laser scanning microphotometer (DWLSM) for in vitro hair shaft and surrounding tissue imaging

To study of human hair pigmentation and morphology one needs an objective and quantitative measure of its optical properties and geometry. Optical transmittance at the selected wavelengths and hair shaft diameter are the parameters, which being measured will satisfy many of medical and cosmetic applications, like laser hair removal,(1-4) studies of the hair phenotype or the hair-color mosaicism,(5) the internal structure examination,(6) or investigation of abnormal melanin aggregation into giant melanosomes for patients with Chediak Higashi syndrome.(7) A few measuring systems for optical and morphological properties of hair fibers are described in literature(4-7) We had developed the double-wavelength laser scanning microphotometer (DWLSM) for biological samples absorbance measuring. Three kinds of work were performed using DWLSM for our studies: the average hair shaft transmittance measuring; the hair transmittance measurements along hair axe; the hair shaft and surrounding tissue imaging. In this paper the principles and construction of DWLSM is described.