1. A method for determining concentration of one or more chromophores in a turbid medium the method comprising: i) measuring an attenuation signal using continuous wave (CW) at a predetermined number of wavelengths; ii) providing a scatter law in which scatter is a function of wavelength; iii) estimating scatter parameters of said provided scatter law and a concentration for the one or more chromophores, said chromophores having a predetermined relationship between chromophore absorption and concentration as a function of wavelength; iv) calculating attenuation values at said predetermined wavelengths using the estimated concentrations and scatter parameters; v) adjusting the concentration for the one or more chromophores and the scatter parameters until the calculated attenuation values and the measured attenuation differ by less than a predetermined value thereby determining said concentration within said medium; and wherein said predetermined number of wavelengths is sufficient to provide a desired degree of accuracy in said determination of said concentration.