Galactography is an x-ray examination that uses mammography, a low-dose x-ray system for examining breasts, and a contrast material to obtain pictures, called galactograms, of the inside of the breast's milk ducts.

The breast is composed primarily of three structures: fat, lobules (that make the milk) and milk ducts (that carry the milk from the lobule to the nipple). While mammography and magnetic resonance imaging (MRI) are excellent ways to image the breast; they cannot visualize the inside of the breast's milk ducts.
The most common use of galactography is to evaluate a woman who has a bloody or clear discharge from her breast nipple and an otherwise normal mammogram.