Differential optical spectropolarimetric imaging system assisted by liquid crystal devices for skin imaging

Abstract

Skin cancer diagnosis depends not only on histopathological examination but also on visual inspection before and after the excision of suspected lesion. Neoplasm is accompanied with changes in birefringence of collagen, pleomorphicity, and hyperchromatic state of epithelial nuclei. These phenomena can be measured by spectral and polarization changes of light backscattered by the examined tissue. A new differential spectropolarimetric system is proposed using liquid crystal devices, one as a tunable filter and the other as a polarization rotator, both operating at wide spectral ranges from the visible to the near-infrared. Since collagen's fibrils texture orientation depends on its location in the skin and since it is not well organized, our system scans the bipolarization states by continuously rotating the linearly polarized light incident on a skin lesion, and collecting differential contrasts between sequenced images when simultaneously averaging the statistical readout of a video camera. This noninvasive method emphasizes areas on skin where the neoplasm, or tumor, minimizes the statistical polarization change of the scattered light from the lesion. The module can be considered as an assistant tool for epiluminescence microscopy. Images of skin tumors were captured in vivo before the patients having their surgery and compared to histopathological results.

Skin Collagen Fiber Molecular Order: A Pattern of Distributional Fiber Orientation as Assessed by Optical Anisotropy and Image Analysis

“…The use of PS-OCT for collagen studies, including those conducted in skin tissues is based on the fact that collagen fibers exhibit optical anisotropic properties such as birefringence. PS-OCT in skin generates back-scattered light that allows the detection of collagen fiber molecular orientation and creates images amenable to measurement [2], [5]–[7].…”

Lenticular arrays based on liquid crystals

“…Nanotechnology works are dealing with carbon nanotubes applications and liquid crys− tal -nanoparticles interactions [2], security is treating cryp− tographic applications [3] and optical communications are handling optical components that are easily integrated in optical fibre systems. Some examples are modulators or fil− ters [4], distributed sensors [5], beam steering devices [6], aberration correction spatial light modulators [7], bio−optics applications [8] and optical lenses [9].…”

Optical configuration of pigmented lesion detection by frequency analysis of skin speckle patterns

“…Recently, simple methods for developing a clear image of the nevus using spectro and polarimetric techniques were presented [34][35][36]. However, the method presented in this paper suggests a new and unique technique in which the physical depth of the nevus tissue is directly analyzed by the vibrational responsivity of the tissue.…”