Backscattering of infrared radiation by a model multilayer biological tissue

The intensity of backscattering of near infrared laser radiation has been calculated for a multilayer biological tissue simulating the human head as a function of the distance between a source and a detector of radiation that are located on the head. The iterative solution of the Bethe–Salpeter equation has been represented as a series in scattering orders. A modification of the known Monte Carlo method for photon transport in multilayer tissues has been proposed to accelerate calculations. It has been shown that the resulting dependences of the backscattering intensity change significantly under the variation of the optical properties of the biological tissue, primarily in the case of penetration of blood to the cerebrospinal fluid layer. This can be used to develop optical methods for diagnosis of traumatic injuries of biological tissues.