A mammogram, or mammography, is a specialized x-ray procedure used to create detailed images of the breast. It is used to detect changes in the breast tissue, such as thickened tissue lumps or calcification that may indicate the presence of breast cancer, and finding them early can significantly increase a patient’s odds of survival. Mammography can detect some abnormalities between one and three years before they can be felt.

Mammograms can be ordered by a physician to detect a variety of breast disorders, ranging from cysts (fluid-filled sacs) to cancer. Mammograms may be ordered to:

• Screen for a condition. Used when women have no signs or symptoms of breast cancer or other breast abnormalities.
  
  
• Diagnose a condition. Used to check for cancer based on signs, symptoms or other test results.
  

Mammograms use special imaging machines  and are usually performed on outpatients. The test is administered by a radiation technologist, usually someone who has been specially trained for mammograms. The mammogram images are stored on films that are reviewed by a physician (physician mammographer) and often additional cancer specialists, for any signs of abnormalities.

Mammogram rates increased steadily from the 1980s until 2000, when they leveled off. However, beginning in 2005, studies showed that mammogram rates dropped significantly, especially among groups of women with previously high screening rates. In a similar timeframe (beginning in 2003), reports of new cases of breast cancer also dropped, according to the American Cancer Society (ACS). Although this information has been hailed as good news, it may be related to cancers undetected because of the decline in screening mammograms.

Mammograms are currently the most effective way to screen for early breast cancer. The ACS recommends that women age 40 and older have a mammogram every year, while the National Cancer Institute recommends mammograms every one to two years for this age group.