Screening mammogram: A mammogram (an X-ray of the breast) in women who have no signs of breast cancer. It usually involves two X-rays of each breast. The aim of a screening mammogram is to detect a tumor that cannot be felt.
A screening mammogram is different from a diagnostic mammogram which involves more X-rays. Diagnostic mammography is done because of the findings on a screening mammogram, evaluate breast changes (such as a lump) or special circumstances, such as breast implants.
Although doubts have been raised as to whether screening mammography prevents breast cancer deaths, in January, 2002 both the National Cancer Institute and the American Cancer Society reiterated their longstanding recommendation that women over 40 have regular mammograms. Controversial recommendation of the US Preventive Services Task Force in 2009 have again raised questions, though most practitioners presently continue to favor the NCI and ACS recommendations.