Table 1.

SAXS features and their relation to the structural components in breast tissue.

SAXS feature	Physically represents
Collagen axial d- spacing	Spacing between the gap-overlap section of the collagen molecules
Collagen axial peak area	Axial peak area defines the combination of peak width and peak amplitude, used herein as an indicator of long-range order in the collagen fibrils. The X-ray constructive interference scattering depends on the abundance of material within the illuminated volume i.e. on parameters such as sample thickness and composition. In general, the larger the area, the greater the degree of long-range order of the samples (i.e. non-lesional).
Collagen axial peak width (full width half maximum- FWHM)	Wide peak corresponds to large variability in the d-spacing. Narrow peaks correspond to low variability in the d-spacing suggesting highly ordered fibrillar collagen overlap spacings
Amorphous scatter	Proportional to the total area per unit mass. Provides information on variation in the electron density of the entire heterogenous sample.
Amorphous scatter between the third and fifth order peak	Integrated intensity between q = 0.2–0.6 nm−1. Used to describe the specific surface area of the scatterers.