Impact of wavelength-dependent refractive indices on scattering and anisotropy spectra in turbid media

Identification of very early-stage cancer (or pre-cancer) and quantitative monitoring of highly-dynamic alterations that can occur as cancer develops, remains an unmet clinical need that, if met, would revolutionize diagnostics and facilitate personalized treatment. Diffuse (and sub-diffuse) reflectance spectroscopy, which quantify the scattering of light by tissue components (e.g., cells, organelles, collagen fibers) have transformative potential for addressing this need. However, it remains challenging to quantitatively connect reflectance data from turbid media to specific biophysical properties of the scatterers (sizes, refractive indices). One important but often-overlooked reason for this difficulty is the wavelength-dependence of the refractive indices of the scatterers and surrounding media. Here, we use Mie Theory to simulate scattering, anisotropy, and reduced scattering spectra for computational models of scatterers with sizes and refractive indices relevant to biological tissues. We show the differences between simulated scattering spectra for models with spectrally-constant versus wavelength-dependent refractive indices of scatterers and surrounding media.