A mammogram is an X-ray of the breast. It can be done to screen for breast cancer and to check lumps in the breast. It can show tumors or abnormal areas that are too small for you or your doctor to feel.

There are different types of mammograms. A 3D mammogram uses X-rays from many angles to make a 3D image of the breast. It is also called digital breast tomosynthesis (say "toh-moh-SIN-thuh-suss"), or DBT. As a newer test, it may not be covered by insurance. Depending on how it is done, a 3D mammogram may use more radiation than a digital mammogram (DM).