The modulations appearing on the backscattering spectrum originating from a scatterer are related to its diameter as
described by Mie theory for spherical particles. Many metrics for Spectroscopic Optical Coherence Tomography (SOCT)
take advantage of this observation in order to enhance the contrast of Optical Coherence Tomography (OCT) images.
However, none of these metrics has achieved high accuracy when calculating the scatterer size. In this work, Mie theory
was used to further investigate the relationship between the degree of modulation in the spectrum and the scatterer size.
From this study, a new spectroscopic metric, the bandwidth of the Correlation of the Derivative (COD) was developed
which is more robust and accurate, compared to previously reported techniques, in the estimation of scatterer size. The
self-normalizing nature of the derivative and the robustness of the first minimum of the correlation as a measure of its
width, offer significant advantages over other spectral analysis approaches especially for scatterer sizes above 3 μm. The
feasibility of this technique was demonstrated using phantom samples containing 6, 10 and 16 μm diameter microspheres
as well as images of normal and cancerous human colon. The results are very promising, suggesting that the proposed
metric could be implemented in OCT spectral analysis for measuring nuclear size distribution in biological tissues. A
technique providing such information would be of great clinical significance since it would allow the detection of
nuclear enlargement at the earliest stages of precancerous development.