Abstract: A diffuse reflectance spectroscopy system for quantifying electromagnetic absorption and scattering in a tissue is provided. Also provided are optical probes and methods for imaging a tissue mass. In some embodiments, the methods include the steps of contacting a tissue mass with an optical probe, wherein the optical probe includes at least one entity for emitting light that interacts with a tissue mass and then is remitted to a collecting entity, for collecting the light that has interacted with the tissue mass, wherein the collecting entity comprises a detector comprising one or more photodiodes; measuring turbid spectral data of the tissue mass using the optical probe; converting the turbid spectral data to at least one of absorption and scattering spectral data via a Monte Carlo algorithm or a diffusion algorithm; and quantifying tissue compositions and scatterer size in a tissue mass using the at least one of absorption and scattering spectral data.