Precision of extracting absorption profiles from weakly scattering media with spectroscopic time-domain optical coherence tomography

The feasibility of spectroscopic optical coherence tomography (SOCT) to quantify spatially localized absorption profiles of chromophores embedded in weakly scattering media with a single measurement over the full spectral bandwidth of the light source was investigated by using a state-of-the-art ultra-broad bandwidth Ti:Al₂O₃ laser (λ_c = 800 nm, Δλ = 260 nm, P_out = 120 mW ex-fiber). The precision of the method as a function of the chromophore absorption, the sample thickness, and different parameters related to the measurement procedure was evaluated both theoretically and experimentally in single and multilayered phantoms. It is demonstrated that in weakly scattering media SOCT is able to extract μ_a(λ) as small as 0.5 mm^-1 from 450 μm thick phantoms with a precision of ∼2% in the central and ∼8% at the edges of the used wavelength region. As expected, in phantoms with the same absorption properties and thickness ∼180 μm the precision of SOCT decreases to >10% in the central wavelength region.