MODEL OF OPTICAL COHERENCE TOMOGRAPHY OF HETEROGENEOUS TISSUE

A comprehensive model of optical coherence tomography (OCT) is describ ed that includes the interference effects that produce speckle in imag es of dense heterogeneous tissue. It is based on the extended Huygens- Fresnel formulation of beam propagation in a turbulent atmosphere, ada pted to the analysis of OCT. Incorporated in the model is a fractal de scription of the size distribution of scatterers in tissue. We demonst rate its application in the simulation of images of tissue volumes con taining high-contrast targets embedded in a mixture of two sizes of pa rticles. The simulated images show the degradation of image quality ca used by speckle noise, along with the benefits of employing a light so urce with a short coherence time and an objective lens with a high num erical aperture. Based on model results, an estimate of the maximum pr obing depth is given in terms of the design variables of an OCT scanne r and the optical properties of the tissue. (C) 1997 Optical Society o f America.