Microscopic origin of light scattering in tissue

Abstract

A newly designed instrument, the static light-scattering (SLS) microscope, which combines light microscopy with SLS, enables us to characterize local light-scattering patterns of thin tissue sections. Each measurement is performed with an illumination beam of 70-microm diameter. On these length scales, tissue is not homogeneous. Both structural ordering and small heterogeneities contribute to the scattering signal. Raw SLS data consist of a two-dimensional intensity distribution map I(theta, phi), showing the dependence of the scattered intensity I on the scattering angle theta and the azimuthal angle phi. In contrast to the majority of experiments and to simulations that consider only the scattering angle, we additionally perform an analysis of the azimuthal dependence I(phi). We estimate different contributions to the azimuthal scattering variation and show that a significant fraction of the azimuthal amplitude is the result of tissue structure. As a demonstration of the importance of the structure-dependent part of the azimuthal signal, we show that this function of the scattered light alone can be used to classify tissue types with surprisingly high specificity and sensitivity.

Label‐Free, Longitudinal Visualization of PDT Response In Vitro with Optical Coherence Tomography

“…Information such as scatterer size, depth, and type can be gleaned from this process and has been used to analyze intact tissue non-destructively. [85] These capabilities have sparked great interest in the past decades in identifying, characterizing, and utilizing scattering for the identification of pathological indicators. [86] …”

Numerical investigation of two-dimensional light scattering patterns of cervical cell nuclei to map dysplastic changes at different epithelial depths

“…If the entire range of polar angles is considered and the integrand is properly normalized, the computed metric gives the scattering cross section that characterizes the overall scattering strength of the nuclei. As these intricate structures are not perfectly spherical and contain refractive index heterogeneities at different length scales, however, their scattering response will exhibit complex azimuthal asymmetry [12][13][14][15][16]. It may thus prove worthwhile to carry out a comprehensive two-dimensional investigation that will enable a comparative assessment of azimuthal dependence in nuclear scattering profiles.…”

Evaluation of a spectrally resolved scattering microscope

“…The contrast is given only by the scattering, so the technique is marker-free and no further enhancement is necessary. Microscopic setups are essential for the study of single cells [13] and chromosomes [14]. Experiments have been made with confocal microscopes [15, 16], brightfield microscopes [17], darkfield microscopes [18] or evanescent illumination [19], just to name a few different methods.…”