How Is a Mammogram Performed?

What You Should Expect at a Mammography Screening

Mature Woman having Mammogram
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A mammogram is a screening tool that uses a special x-ray to examine breast tissue to see if any abnormal growths or tissue are present.

Why Is a Mammogram Performed?

Mammograms are a regular part of women's healthcare and are done as a screening tool for breast cancer.

Mammogram screening is done for women who have no symptoms, but imaging tests can also be used in women who have symptoms, such as a lump or pain in the breast, or who have a suspicious change originally detected on a screening mammogram.

The procedure is also performed to examine a lump or growth.

How Is the Procedure Performed?

During a mammogram, a woman's breast are compressed with a special machine. Images of each breast are taken with special x-ray film that is designed for breast tissue. Images are taken from different angles.

Screening Mammograms — like the ones used for women without symptoms or signs of breast cancer involve taking 2 x-ray pictures (views) of each breast. Women with larger breasts may need to have more pictures to see as much breast tissue as possible.

Diagnostic Mammograms — If you are experiencing a breast problem such as a lump or nipple discharge, or an abnormal area found in a screening mammogram, you would typically gets a diagnostic mammogram. A radiologist reviews mammogram images while you are having a diagnostic mammogram so that more images can be taken of an area of concern if a closer look is needed.

Sometimes special images called spot views or magnification views are used in order to evaluate mall areas of concern.

A diagnostic mammogram may reveal:

  • that an area that looked abnormal on a screening mammogram is actually normal. If this is the case, you may go back to routine yearly screening.
  • that an area of concern probably is not cancer, but your radiologist may want to watch the area closely so it’s common to ask you to return to be re-checked, usually in 4 to 6 months.
  • that a biopsy is needed to find out if the abnormal area is cancer. If your doctor recommends a biopsy, it does not actually mean that you have cancer. Be sure to discuss the different types of biopsy with your doctor to decide which type may be best for you.

How to Prepare for a Mammography and What to Expect

There are no special precautions to take prior to a mammogram but you must be careful not to wear lotions, deodorants, powders, or creams on your chest before the procedure as all of these substances can conflict with the imaging.

On the day of the procedure:

  • consider wearing a 2 piece outfit as you will be asked to undress from the waist up.
  • you will be provided with a hospital type gown
  • you and a technologist will be in a screening room alone during the mammogram. The technologist will position your breast in order to get a high quality picture (the breast must be somewhat flattened)
  • the technologist places the breast on the machine’s plate and the plastic upper plate is lowered to compress the breast for a few seconds while the picture is taken.
  • The whole procedure takes about 20 minutes.

You should have a summary of your results in simple language within 30 days and usually you will be contacted within 5 working days if there’s a possible problem detected on the mammogram.

It's important to note that only 2 to 4 screening mammograms out of every 1,000 lead to a diagnosis of breast cancer.

Possible Complications

You may have slight skin irritation or aching from the compression after the mammogram. Most doctors recommend an over the counter pain reliever.

Fortunately radiation exposure is not as big a problem as it once was since the x-ray machines used for mammograms expose the breast to much less radiation than machines used in the past. 

More About Mammograms and Breast Cancer


American Cancer Society. Mammograms and Other Breast Imaging Tests. Accessed 25 March 2016.

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