Quantification of breast tissue constituents from time-resolved reflectance spectra

The optical properties of the breast of a 35 yr. old volunteer were studied as a function of the menstrual period using a system for time resolved reflectance spectroscopy from 610 to 1000 nm. The availability of a wide spectral range allowed us to derive the mean concentration of the main tissue absorbers (water, lipids, oxy-, and deoxyhemoglobin), and to infer information on the microscopic structure. Reflectance spectra were richer of blood and lipids, while transmittance spectra showed a more marked water peak. Changes of absorption properties were observed as a function of phases within tile menstrual cycle with an increase in blood and lipid absorption in reflectance and of water content in transmittance while approaching menstruation. Scattering spectra experienced a drop in slope across ovulation, suggesting a change in size and structure of scatterers. This spectroscopy technique can be of great help to understand breast physiology from an optical point of view, and to help further improvement of optical mammography.