MAMMOGRAPHY

What is a mammogram?

Mammography is a test that uses X-rays to create images of the breast. These images are called mammograms.

A radiologist trained to read mammograms studies the images and looks for signs of breast cancer.

Digital mammography

In the past, mammogram images were stored on film (film mammography). Now, mammogram images are usually stored on a computer (digital mammography). This makes it easy to share digital images with another radiologist for review.

Digital mammography images are viewed on a computer. They can be lightened or darkened, and certain sections can be enlarged and looked at more closely.

How is mammography used?

Screening

Breast cancer screening tools are used to find breast cancer in a person who doesn’t have any warning signs or symptoms.

Overall, mammography is the most effective screening tool used to find breast cancer in most women. It can find cancers at an early stage, when they are small and the chances of survival are highest.

Learn about mammography recommendations for women at average risk of breast cancer.

Learn about mammography recommendations for women at higher than average risk of breast cancer.

Follow-up

Mammography can be used as a follow-up test when something abnormal is found on a screening mammogram or a clinical breast exam.

A mammogram used as a follow-up test (instead of screening), may be called a “diagnostic mammogram.” Although it’s called a “diagnostic mammogram,” it can’t diagnose breast cancer. It can show whether the abnormal findings look like breast cancer though.

If the findings look like breast cancer, you’ll need a biopsy to diagnose (or rule out) breast cancer.

Whether you’re getting a screening mammogram or a diagnostic mammogram, the basic procedure is the same. However, you’ll likely have more views with a diagnostic mammogram. 

Getting a mammogram

If you’re getting a mammogram for the first time, you may have questions about what to expect (before and after).

Learn about getting a mammogram, including information for women who have breast implants, are pregnant or breastfeeding, or who have a physical disability.

Findings on a mammogram

Like other X-ray images, mammograms appear in shades of black, gray and white, depending on the density of the tissue. Dense breast tissue looks different from fatty breast tissue on a mammogram.

Learn more about breast density on a mammogram.

A mammogram may show:

• No signs of breast cancer
• A benign (not cancer) condition
• An abnormal finding that needs follow-up tests to rule out cancer

Learn more about findings on a mammogram and when to expect your results.

Follow-up after an abnormal mammogram

If your mammogram shows something abnormal, you will need follow-up tests to check whether or not the finding is breast cancer.

Learn about follow-up after an abnormal mammogram.

Learn about follow-up after an abnormal clinical breast exam.

Accuracy of mammograms

Although mammography is the most effective screening tool used today to find breast cancer in most women, it’s not perfect.

Learn about the accuracy of mammograms.

	For a summary of research studies on mammography in women ages 40-49, visit the Breast Cancer Research Studies section.
	For a summary of research studies on mammography in women ages 50-69, visit the Breast Cancer Research Studies section.
	For a summary of research studies on 3D mammography for breast cancer screening, visit the Breast Cancer Research Studies section.

Weighing the risks and benefits of mammography

Most major health organizations agree mammography lowers a woman’s risk of dying from breast cancer [2-4].

However, there’s ongoing debate about how much benefit there is from mammography (especially in younger women) and whether this benefit outweighs the risks.

There’s also debate about when to begin mammography and how often to get a mammogram.  

Learn more about the benefits and risks of mammography.

Radiation exposure during a mammogram

You’re exposed to a small amount of radiation during a mammogram.

While the radiation exposure during a mammogram might increase the risk of breast cancer over time, this increase in risk is very small [5-7].

Studies show the benefits of mammography outweigh the very small risks from radiation exposure, especially for women ages 50 and older [5-6,8].  

Three-dimensional (3D) mammography (breast tomosynthesis)

What is 3D mammography?

A 3-dimensional (3D) mammography machine takes multiple 2-dimensional (2D) digital images of the breast. Computer software combines the 2D images into a 3D image (called breast tomosynthesis).

Radiologists must have special training to read these 3D images.

Getting a 3D mammogram

Getting a 3D mammogram is similar to getting a 2D mammogram.

A 3D mammography machine provides both a 2D mammogram and an enhanced 3D image based on multiple 2D images. All the images are taken on the same machine, so you stay in one place while all of the images are taken.

A 3D mammogram takes a few seconds longer than a 2D mammogram because more images are taken. You may not notice a difference (if you’ve had a 2D mammogram in the past).

3D mammography gives a slightly higher radiation dose than standard 2D mammography. This higher dose is still within FDA guidelines [4,9-10]. Some machines give a lower radiation dose than others [4].

Breast cancer screening with 3D mammography

Some studies have shown 3D mammography may find a few more breast cancers than 2D mammography [9-10,11-14]. Whether 3D mammography is better than standard 2D mammography for breast cancer screening is still under study [9-10,11-14].

Currently, the American Cancer Society and the U.S. Preventive Services Task Force recommend standard 2D mammograms in their breast cancer screening guidelines [2-3].

The National Comprehensive Cancer Network guidelines, however, note 3D mammography may be considered for breast cancer screening [4].

Some centers offer 3D mammography. Although most insurance plans cover the cost, it’s best to check with your insurance provider and the imaging center before getting a 3D mammogram.

Learn more about screening recommendations for women at average risk. 

For a summary of research studies on 3D mammography for breast cancer screening, visit the Breast Cancer Research Studies section.

Low-cost or free mammograms

Medicare, Medicaid and most insurance companies cover the cost of mammograms.

Since September 2010, the Affordable Care Act has required all new health insurance plans to cover screening mammograms every 1-2 years with no out-of-pocket costs (co-payments or co-insurance) for women ages 40 and older [15].

If you don’t have insurance or your insurance doesn’t cover mammograms, the resources below may help you find a low-cost or free mammogram (or help with the cost).

• ABCF fund breast cancer education and screening projects in their communities. 

• The National Breast and Cervical Cancer Early Detection Program provides access to breast cancer screening (plus diagnostic testing if results are abnormal, and referrals to treatment if breast cancer is diagnosed) to low-income, uninsured and underinsured women ages 40-64. 
• Planned Parenthood offers clinical breast exams and referrals for mammography (and any follow-up testing, such as breast ultrasound).

Each October, during Breast Cancer Awareness Month, many imaging centers offer mammograms at reduced rates. To find a certified mammography center in your area, visit the FDA website (www.fda.gov).

Updated 08/6/19