Screening Mammograms


This page explains screening mammograms, imaging exams that are done to find breast cancer.

What is a screening mammogram?

A mammogram is an imaging test to find breast cancer. It uses X-rays to take images of the breasts.

A specially trained female technologist will help you get in the right position to take images of your breasts.
There are 2 types of mammograms:

  • Screening mammograms are used to find breast cancer in women who do not have breast symptoms or complaints.
  • Diagnostic mammograms are used to look for the cause of a symptom, such as a lump in the breast.

Why should I have a screening mammogram?

Screening mammograms help find breast cancers early, before you or your doctor can feel any changes in your breasts. This means we find the cancer when it is smaller and can be treated more easily. This can save a woman's life. When cancer is found early, the chance of cure is higher.

When should I get a screening mammogram?

Several groups have guidelines about screening mammograms, including the American Cancer Society (ACS), the United States Preventive Services Task Force (USPSTF), and the National Comprehensive Cancer Network (NCCN). Each of these groups suggests a different timeline for testing. All groups agree that starting yearly screening mammography at age 40 saves the most lives.

  • That's why both the ACS and the NCCN agree that women with an average risk for breast cancer should have the choice to start yearly screening mammograms at age 40. All of the groups recognize that each woman might make a different decision about when and how often to have screening. 
  • Some women might choose to start screening later than age 40. They may also choose to have screening less often, such as every other year. 
  • Women with higher risk for breast cancer should start screening earlier than age 40. 
  • Screening mammograms may not be a good idea for women who have other serious health problems.
  • Please talk with your doctor about your breast cancer risk, your values, and your desires. Together, you can make the choice that is best for you. 

More About Mammograms

X-rays taken during a mammogram are used to make 2D (conventional) and 3D (tomosynthesis) images. Both types of images help find breast cancer.

  • For 2D mammograms, an image of each breast is taken in 2 views: a top-to-bottom view and a side view.
  • 3D mammograms take many images in the same 2 views. This creates a stack of very thin images called slices.

3D mammograms help your radiologist see any unhealthy tissue more clearly. This may lessen the need for follow-up tests of tissue that may appear abnormal on 2D mammograms. That's why the University of Washington Medical Center (UWMC) and Seattle Cancer Care Alliance (SCCA) now use 3D mammograms most of the time.

​As of June 2018, health insurance providers in Washington state are required to cover tomosynthesis under the same terms and conditions as they cover screening mammography.

What are the risks of getting a mammogram?

For most women, the benefits of getting a mammogram outweigh the risks. But, like all tests, mammograms have some risks:

  • Most breast cancers can be seen on mammograms, but some cannot. If you have breast concerns, talk with your doctor or breast health specialist about your symptoms. It is important to do this even if you just had a mammogram that did not show any problems.
  • A mammogram can result in a "false alarm." A false alarm is when a mammogram shows a possible problem that turns out to not be cancer after more tests are done. These tests may include more imaging exams or having a small tissue sample (biopsy) taken for testing in the lab. 
  • At UWMC and SCCA, false alarms occur for less than 10% of women (fewer than 10 out of 100 women). This is better than the average rate for healthcare facilities in the U.S.

Are mammograms safe?

When you have a mammogram, you are exposed to a low level of radiation. In our daily lives, we are all exposed to the "background radiation" that is found in nature. The radiation you receive from a mammogram is about the same that someone living in the U.S. picks up from nature over a 2-month period.

This low dose of radiation is very safe and is not likely to harm your health. If you have any questions about radiation, please talk with your technologist (the person who takes the images of your breasts) or doctor on the day of your exam.

How do I prepare for a mammogram?

On the day of your exam:

  • Do not put deodorant, talcum powder, or lotion under your arms or on your breasts. This will help ensure that your images are the best quality.
  • Bring any past mammograms (if you have them) with you. These are helpful to the doctor (radiologist) who will look at your images.

Before your exam, tell your doctor or technologist if you:

  • Have any new problems in your breasts
  • Have a history of breast surgeries, biopsies, or implants
  • Are taking medicine that contains hormones or affects the hormone levels in your body
  • Have a family or personal history of breast cancer
  • Are pregnant, or if there is any chance you might be pregnant

What should I expect during the mammogram?

First, a specially trained female technologist will help you get in the right position. Your breast will be placed on a special platform and briefly compressed with a paddle. Images are taken of one breast at a time. The entire exam takes about 15 minutes.

  • It is normal to feel pressure on your breast when it is compressed by the paddle for each image.
  • Tell the technologist if you feel pain. Our technologists will do all they can to make you as comfortable as possible.

Who interprets the results?

An expert trained in breast imaging will read and interpret your images. The UWMC and SCCA radiologists who read mammograms are certified by the American Board of Radiology and have received extra training in breast imaging. Our radiologists exceed the national criteria for excellence.

How do I get the results?

You will receive a letter with your results in the mail in 7 to 10 working days. Your healthcare provider will also receive a report and can answer any questions you have.

If it has been 10 days since your mammogram and you have not received your results letter, please call 206.606.7800.

What if my results letter asks me to return for more tests?

Your letter may ask you to return for more mammogram images or for an ultrasound. Please do not worry if this happens. This is fairly common. It only means that the radiologist would like a better look at areas of your breast. Or, some images may need to be done again because of technical problems with your first mammogram.

It is important that you return for this extra imaging. We may use different methods and equipment to make sure we get very clear images.​

To schedule extra imaging, please call 206.606.7800.


Your questions are important. Call your doctor or healthcare provider if you have questions or concerns.​

  • SCCA Breast Imaging: 206.606.7800​