Numerical simulation of optical coherence tomography interference signal occurring in the intravascular space under a layer of soft biological tissue

A numerical simulation algorithm of the interference signal acquired from biological fluids' flow in Doppler optical coherence tomography (OCT) system is described. The suggested numerical approach has four key features: i) hydrodynamic characteristics of the part of the geometric layout in the intravascular space are not static, but dynamically change in numerical simulation of the photon transport; ii) dynamic changes include fluctuations of the optical characteristics and geometry of the parts of the intravascular space and were made for all pixels (B-scan) or voxels (C-scan) of the acquired data; iii) pixels and voxels of the intravascular space are considered to have the optical properties either of blood plasma or of the red blood cells; iv) the flow velocity is different for different types of pixels (voxels) which replace each other in the intravascular space: v) velocity value is chosen to obtain the desired shape of the flow velocity profile. The numerical model of the flow with a complex structure in soft biological tissues was implemented as the dedicated software using the LabVIEW package. The interference signal (A-scan) simulating software was successfully tested using hydrodynamic phantoms and can be used to study flow characteristics and their dynamic changes.