Complex refractive index of freshly excised human breast tissue as a marker of disease.

We report differences in the refractive index of healthy and tumorous freshly excised human breast tissue as determined from reflectance profile measurements at five wavelengths (432 nm, 532 nm, 633 nm, 964 nm, 1551 nm) in the visible and near-infrared using a standard prism-coupling refractometer. These refractive index differences, particularly in the near-infrared, can be used to distinguish fibroadenomas and cancerous growths not only from normal breast tissue but also from each other.