Brain glial tumors have peculiar features of the perifocal region extension, characterized by its indistinct area, which complicates determination of the borders for tissue resection. In the present study filter-reduced back-scattered laser light signals, compared to the data from mathematical modeling, were used for description of the brain white matter. The simulations of the scattered light distributions were performed in a Monte Carlo program using scattering and absorption parameters of the different grades of the brain glial tumors. The parameters were obtained by the Mie calculations for three main types of scatterers: myelinated axon fibers, cell nuclei and mitochondria. It was revealed that diffuse-reflected light, measured at the perifocal areas of the glial brain tumors, shows a significant difference relative to the signal, measured at the normal tissue, which signifies the possibility to provide diagnostically useful information on the tissue state, and to determine the borders of the tumor, thus to reduce the recurrence appearance. Differences in the values of ratios of diffuse reflectance from active growth parts of tumors and normal white matter can be useful for determination of the degree of tumor progress during the spectroscopic analysis.
