(HealthDay News) -- Most doctors agree that a woman should have a baseline mammogram at age 40, then every one-to-two years afterward.
However, according to the National Cancer Institute, women with certain histories may need to go earlier and more frequently.
Women who have had breast cancer, have a family history of breast cancer, or who have certain genetic alterations need to be screened more frequently.
There are two kinds of mammograms -- screening and diagnostic. A screening mammogram is an x-ray of the breast used to detect changes in women who have no symptoms of breast cancer.
A diagnostic mammogram is an x-ray of the breast to diagnose unusual changes such as a lump, pain, nipple discharge or a change in breast size or shape.
If these types of changes need further study, usually an ultra-sound -- and in some cases, an MRI -- is recommended.
