ИСТИНА

To increase the depth of penetration of visible and near-infrared radiation into the biological tissues to enhance the efficacy of diagnostic and therapeutic procedures, numerous techniques are used to increase the image contrast, in particular, optical clearing. Typically, optical clearing agents (OCAs) are used for this purpose. The mechanism of the OCA action is based on the reduction of the reflectance from the tissue surface and diffuse penetration of the OCA into the deep layers of tissues. The second process results in the reduction of the amount of multiple light scattering by equalizing the relative refractive index of the light scattering nonhomogeneities inside the investigated tissue. These makes the tissues optically more homogeneous, which results in the increase of the depth and resolution of imaging techniques, for example the digital capillaroscopy method for in vivo visualization of terminal capillaries in the nail bed area. One of the aims of this work was to study the efficacy of various OCA which are already used in clinical practice as radiopaque substances for improving the visualization of subsurface structures in vivo. The measurements were taken within the nail bed using optical coherence tomography (OCT). Another goal of this work was to investigate the effect of these OCA on the aggregation of rat’s red blood cells (RBCs) to study the mechanisms of OCAs affecting the blood flow after their administration into the blood stream. To study this effect in vitro laser aggregometry method was used.