Theoretical comparison of light sources for use in optical coherence tomography

摘要

The suitability of a source for OCT depends in part on its characteristics and the heterogeneity of the tissue involved. Published source and tissue optical property data has been used to quantify the performance of various sources for use in OCT on skin and liver. Absorption and scattering coefficients were used to estimate the amount of incident light returning from 20, 200 and 400micron depths and the mean free path of light at wavelengths in the range 500 to 2100nm. Conclusions were based on changes in intensity and bandwidth of light on travel through tissue. A tungsten halogen lamp gave the best resulting intensity and resolution of all sources studied, however its suitability for OCT would be dependent upon achieving enough spatially coherent power in a small area to achieve adequate transverse resolutions. Although the bandwidth of pulsed Cr:forsterite laser light decreases with travel through tissue, it can be used to obtain higher resolution images than radiation from most other sources. While they showed the second to highest resolution, pulsed Ti:sapphire lasers would be suited to acquiring shallower OCT images, as the radiation has the shortest mean free path and is strongly attenuated. For low-resolution applications, Yb fibre sources have superior powers and bandwidths than the superluminescent diode studied.