A mammogram is an x-ray picture of the breasts. It is used to find tumors and to help tell the difference between noncancerous (benign) and cancerous (malignant) disease.
How the test is performed
You will be asked to undress from the waist up and will be given a gown to wear. Depending on the type of equipment used, you will sit or stand.
One breast at a time is rested on a flat surface that contains the x-ray plate. A device called a compressor will be pressed firmly against the breast to help flatten out the breast tissue.
The x-ray pictures are taken from several angles. You may be asked to hold your breath as each picture is taken.
Sometimes you will be asked to come back at a later date for more mammogram images. This does not always mean you have breast cancer. Rather, the doctor may simply need to recheck an area that could not be clearly seen on the first test.
Digital mammography is a newer technique that allows the x-ray image of the breast to be viewed and manipulated on a computer screen. It improves accuracy, but it is not yet available everywhere.
How to prepare for the test
Do not wear deodorant, perfume, powders, or ointments under your arms or on your breasts on the day of the mammogram. These substances may hide the images. Remove all jewelry from your neck and chest area.
Tell your health care provider and the radiologist if you are pregnant or breastfeeding.
How the test will feel
The metal may feel cold. When the breast is pressed down, you may have some pain. However, this needs to be done to get good images.
The level of radiation is low, and any risk from mammography is very low. If you are pregnant and need to have an abnormality checked, your belly area will be covered and protected by a lead apron.
Routine screening mammography is not done during pregnancy or while breastfeeding.
Qaseem A, Snow V, Sherif K, et al. Screening mammography for women 40 to 49 years of age: A clinical practice guideline from the American College of Physicians. Ann Intern Med. 2007;146(7):511-515.
Smith RA, Saslow D, Sawyer KA, et al. American Cancer Society guidelines for breast cancer screening: Update 2003. CA Cancer J Clin. 2003;53(3):141-169.
Davidson N. Breast cancer and benign breast disorders.In: Goldman L, Schafer AI, eds.Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 204.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.