Natalia Trunina, Saratov State University, Russia
Vladimir Derbov, Saratov State University, Russia
Valery Tuchin, Saratov State Univerisy, Russia
A simple numerical model is proposed to describe the process of OCT signal formation in a scattering medium (biotissue) under the conditions of immersion chemical agent diffusion. Due to optical clearing of the biotissue the shape of the OCT A-scan becomes time-dependent, thus providing information about the diffusion rate. The model includes the numerical solution of the diffusion equation, the relation between the concentration of clearing agent and the scattering coefficient, and, finally, the description of the OCT signal formation given the material parameters and with the probe beam geometry taken into account. The test calculations qualitatively reproduce the experimentally observed time behavior of A-scans in samples of human tooth dentine, caused by diffusion of different chemical agents. In particular, it is shown that the non-monotonic A-scans having a maximum can be explained by assuming that the backscattering coefficient giving rise to the OCT signal is, at least partially, subject to optical clearing alongside with the scattering coefficient responsible for the signal attenuation.
Prof. Vladimir Leonardovich Derbov
Saratov State University, professor
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