Abstract: Provided is a spatially resolved diffusive reflectance spectroscopy apparatus that includes an emitter, a plurality of optical waveguides, a switch, a photon detector, and a controller, and a method for operation of the apparatus. The controller controls emitter intensity, identifies photons detected by the photon detector as belonging to a specific optical waveguide of the plurality of optical waveguides, counts the detected photons, and identifies respective optical waveguides receiving each counted photon. The emitter emits optical photons in an optically turbid medium, and a distal end of each optical waveguide of the plurality of optical waveguides receives the optical photons reflected or scattered in the optically turbid medium.