DOT of intrinsic breast contrast at 754 nm. The figures display the distribution of (a) the absorption and (b) reduced scattering coefficient from a patient with a well-localized 3.4-cm fibroadenoma in the upper central region of her breast. The geometry is a single plane transecting the location of the abnormality, in a craniocaudal view. The lesion appears to have higher absorption than the average background breast absorption, possibly due to increased vascularization. No significant scattering contrast is obtained. Spectral information, namely the combination of such images at multiple wavelengths, can quantify the vascularization and oxygenation level of breast lesions. From Pogue et al , with permission of the Radiological Society of North America.