1. A spectrophotometer for providing an image of a radiation scattering medium having one or more radiation attenuating constituents, comprising: light source means for illuminating said medium from a source location at a time t.sub.0 with electromagnetic radiation of at least one wavelength, said electromagnetic radiation propagating through said medium over a plurality of paths; means for detecting, during a set of detection windows commencing at selected times relative to time t.sub.0, portions of said electromagnetic radiation emerging from said medium at a first detection location after having propagated through said medium from said source location to said first detection location over a corresponding set of paths of selected length; intensity measuring means for measuring intensity of each of said detected portions of electromagnetic radiation during said detection windows wherein said measured intensities are a function of attenuation of said region; and means for generating said image based upon said intensities measured during each of said detection windows and upon corresponding ones of said paths of selected length.