Backscattering of linearly polarized light from turbid tissue-like scattering medium with rough surface

Abstract

In the framework of further development of a unified computational tool for the needs of biomedical optics, we introduce an electric field Monte Carlo (MC) model for simulation of backscattering of coherent linearly polarized light from a turbid tissue-like scattering medium with a rough surface. We consider the laser speckle patterns formation and the role of surface roughness in the depolarization of linearly polarized light backscattered from the medium. The mutual phase shifts due to the photons’ pathlength difference within the medium and due to reflection/refraction on the rough surface of the medium are taken into account. The validation of the model includes the creation of the phantoms of various roughness and optical properties, measurements of co- and cross-polarized components of the backscattered/reflected light, its analysis and extensive computer modeling accelerated by parallel computing on the NVIDIA graphics processing units using compute unified device architecture (CUDA). The analysis of the spatial intensity distribution is based on second-order statistics that shows a strong correlation with the surface roughness, both with the results of modeling and experiment. The results of modeling show a good agreement with the results of experimental measurements on phantoms mimicking human skin. The developed MC approach can be used for the direct simulation of light scattered by the turbid scattering medium with various roughness of the surface.

In vivo laser speckle measurements of skin roughness: clinical study

“…The in-vivo clinical study demonstrated that melanomas have a lower surface roughness value than that of the SK and, interestingly, surface roughness could be a reasonably good parameter to differentiate these two highly look-alike lesions. Further improvement in measurement can be achieved if calibration curve will be calculated by MC [7] based on real optical properties of tissue of interests instead of taking from artificial phantoms.…”

A review of polarization-based imaging technologies for clinical and preclinical applications

“…In an extensive clinical study (214 lesions total), she showed that statistical moments of the polarization speckle pattern could be used to differentiate skin lesions. The fourth order moment was used to differentiate melanoma and seborrheic keratosis with very promising sensitivity [136,137]. This approach relies, in large part, on scattering from the skin lesion rough surface, hence the mechanism is similar to the one proposed by Ghassemi et al using incoherent polarized light [59].…”

Advances in Monte Carlo Simulation for Light Propagation in Tissue

“…Another example of rough surface compensation is seen in simulation of back scattering of coherent linearly polarized light from tissue [76]. Electric field MC was introduced by Doronin et al, which considered the laser speckle and depolarization of the linearly polarized light back scattered from the tissue due to surface roughness.…”

“…CUDA and graphical processing unit (GPU) were used to speed-up the light propagation. Simulation with 10 11 photons took approximately 2 hours [76]. The roughness parameter was varied from 0 to 65.8 µm.…”