MECHANISMS OF LIGHT-SCATTERING FROM BIOLOGICAL CELLS RELEVANT TO NONINVASIVE OPTICAL-TISSUE DIAGNOSTICS

We have studied the optical properties of mammalian cell suspensions t o provide a mechanistic basis for interpreting the optical properties of tissues in vivo. Measurements of the wavelength dependence of the r educed scattering coefficient and measurements of the phase function d emonstrated that there is a distribution of scatterer sizes. The volum es of the scatterers are equivalent to those of spheres with diameters in the range between similar to 0.4 and 2.0 mu m. Measurements of iso lated organelles indicate that mitochondria and other similarly sized organelles are responsible for scattering at large angles, whereas nuc lei are responsible for small-angle scattering. Therefore optical diag nostics are expected to be sensitive to organelle morphology but not d irectly to the size and shape of the cells. (C) 1998 Optical Society o f America.