Mammography

Mammography uses x-rays, high contrast/high resolution film, and a specially designed x-ray machine to collect detailed images of the breasts. These images can help detect early stages of breast cancer by showing changes in the breasts long before you or your doctor can feel them.

Annual mammograms are recommended for women beginning at age 40. For women who have family members with a history of breast cancer, however, mammograms are usually recommended at an earlier age. Your doctor may also suggest you have a baseline mammogram. This is a mammogram done when you are younger that provides an initial image for use in comparing with later mammograms.

There are two types of mammograms, screening and diagnostic. Screening mammograms are used to find changes in the breasts of women who have not detected anything themselves and have no symptoms of a problem. (Referred to as "asymptomatic.")

Diagnostic mammograms are done when you or your doctor have detected a lump or noticed nipple discharge, or when a screening mammogram has revealed an abnormality.

How mammography works
A mammogram is basically just an x-ray made on very high contrast, high resolution film, and done with a specially designed x-ray machine. The x-rays pass through the breast from above to a film cassette below the breast. There is a special phosphor coating inside the cassette that glows in direct proportion with the x-ray beams that are hitting it to enhance the image. The energy and wavelength of the x-rays allow them to pass through the breast while being absorbed at different rates by different types of tissues. These variations in absorption create the differences in exposures that provide the details of the tissues inside the breast. A very low dose of radiation is used for this type of x-ray.

The x-rays are then developed in a dark room or other film processor, much like photographic film is developed. On the film, fat appears black, but everything else (glands, connective tissues, tumors, calcifications, etc.) appears in varying shades of white and gray.

Digital mammography is a recent advance that uses the same x-ray technology, but rather than putting the images on film the information is digitized and sent to a computer. Digital mammography allows the radiologist to vary the magnification and contrast on the computer to better see the variations of the breast tissue. This method of mammography is also quicker and provides immediate images for the technician to review for quality.

What to expect when you have a mammogram:
It is best to have your mammogram one week after your period so your breasts will be less tender. The day of your appointment don't wear any perfume, lotion, powder, or deodorant under your arms or on your breasts because they can cause shadows on the mammogram. It is also easiest to dress in pants or a skirt with a separate shirt so you don't have to undress completely while you're having the mammogram.

When it is time for the mammogram, the RRA x-ray technician will place adhesive skin markers on your breast to identify moles, scars, or other blemishes, or to indicate the position of a lump that has been detected. They will then position you in front of the mammogram machine and place one of your breasts between two plastic plates. These plates press down on your breast to flatten it so the image can show the most tissue detail. By getting the breast flatter, they can use a lower level of radiation for imaging. The compression may be a little bit uncomfortable, but should not produce significant pain. If it does, alert the technician so adjustments can be made. There will be two images taken of each breast. Each compression should only last a few seconds. Because most breast cancers develop from glandular tissue and occur centrally and laterally in the breast, it is very important that these areas show up very clearly on the film.

If you are having a diagnostic mammogram, it will take longer because additional information has to be gathered, and more views of the breast imaged.

Once the technician is satisfied with the quality of the films, you will be free to go. You will receive notification of the results of your mammogram within one week, most often by mail.

If you are having digital mammography it will be even quicker. With this technology, images are seen immediately so the technician can review the quality without having to process the film.

Once the imaging is complete, an RRA radiologist interprets them to determine if there are any abnormalities and confers with your physician about their findings.

Internet Links
National Institutes of Health: Screening Mammograms Fact Sheet