Breast cancer screening detects cancer and saves lives. Mammograms have been the best tool for a long time. When combined with digital breast tomosynthesis, or DBT (3D mammograms), mammograms are far more likely to detect cancer, especially in dense breast tissue.


Comparison of 2D mammography and tomosynthesis
Providers may use 2D mammograms or tomosynthesis for breast cancer screenings, but tomosynthesis is better at detecting cancer in dense breast tissue.

What is digital breast tomosynthesis (3D mammography)?

Digital breast tomosynthesis (pronounced “toh-moh-SIN-thah-sis”) is a technologically advanced mammogram that’s excellent at detecting breast cancer, especially in dense breast tissue. Breast tomosynthesis is also known as 3D mammography because it uses a series of two-dimensional images to build a three-dimensional image of your breast. Standard mammography, still considered the most reliable procedure for breast cancer screenings, takes 2D images of breasts.

The U.S. Food and Drug Administration (FDA) approved digital breast tomosynthesis (DBT) in 2011. Given how effectively DBT detects cancer, it may eventually become the new gold standard in breast imaging.

Who should have digital breast tomosynthesis?

Anyone who needs a mammogram can potentially benefit from DBT, but it’s especially beneficial if you have dense (as opposed to fatty) breast tissue. About half of women and people assigned female at birth (AFAB) have dense breasts. The denser your breast tissue, the harder it is to spot cancer on a standard 2D mammogram.

Like standard mammograms, DBT uses low-dose X-rays to take images of the inside of your breast. Dense (thick or compacted) tissue — including bone, solid tumors and dense breast tissue — absorbs more radiation from the X-ray, making it appear white on a mammogram. Distinguishing between cancer and dense breast tissue can be tricky, as they both appear white on imaging.

Digital breast tomosynthesis takes multiple pictures of your breast from more angles than a standard mammogram, creating a more detailed image. DBT reveals cancers that may have otherwise been “hidden” in dense breast tissue. It correctly identifies normal tissue that may appear “suspicious” or potentially cancerous on a standard mammogram. In this way, DBT decreases the frequency of a false-positive result (learning that you may have cancer when you really don’t).

When would breast tomosynthesis be needed?

Digital breast tomosynthesis is a:

  • Screening procedure. The US Preventive Services Task Force recommends that all people assigned female at birth (AFAB) start having screening mammograms at age 40. You may need to start screening earlier if you have a strong family history of breast cancer. Breast tomosynthesis is one option. Like a traditional mammogram, DBT can detect cancer in its early stages, before you develop symptoms.
  • Diagnostic procedure. Your healthcare provider may order digital breast tomosynthesis if you have breast cancer symptoms, like breast pain, a lump in your breast or skin changes. A breast tomosynthesis can help your provider rule out cancer or determine if you need a biopsy to check for cancer cells.


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Test Details

Early detection is key when it comes to diagnosing and treating breast cancer. Healthcare providers use traditional mammography and tomosynthesis (3D mammography) to screen for new masses or other signs of cancer in your breast tissue.

Who performs digital breast tomosynthesis?

A radiologic technologist or mammographer will position you for the procedure and operate the mammography machine. A radiologist will analyze the images and communicate test results with your referring provider.

How does digital breast tomosynthesis work?

Digital breast tomosynthesis (DBT) is similar to a standard mammogram. The major difference is that it takes more pictures of your breast from more angles to capture more detail.

During a standard mammogram, your breast is positioned on a flat support and compressed (squeezed) between two horizontal plates. The machine takes 2D images of your breast from two angles, top to bottom and side to side.

During DBT, your breast is positioned and compressed the same way it is for a 2D mammogram. However, during breast tomosynthesis, the arm of the mammogram machine (X-ray tube) moves in an arc over your breast, taking many 2D images from multiple angles as it moves.

The 2D images get digitized and fed into a computer that combines them into a 3D image. The 3D image shows more details, making it easier to tell the difference between healthy and potentially cancerous tissue.


How do I prepare for digital breast tomosynthesis?

Ensure your healthcare provider is fully informed about your medical history — especially your breast health. To prepare:

  • Review your medical history with your healthcare provider. Tell your provider about any breast conditions, surgeries, recent vaccines and hormones you’re taking. Let them know about your family’s breast cancer history. Your provider will also need to know if you’re pregnant or breastfeeding (chestfeeding).
  • Have previous results sent to your current provider. If you previously had a mammogram at a different facility, arrange to have the images sent to your current provider. Comparing previous images to current ones makes it easier to spot abnormalities.
  • Schedule your appointment for when your breasts aren’t tender. Your breasts are least likely to be tender the first week or two after your period ends. This is the best time to schedule a mammogram.

What to expect on the date of the test?

Plan for the procedure to take about 30 minutes. You’ll go home that same day. To prepare:

  • Shower as you normally would, but don’t apply any deodorants, powders, lotions or similar grooming products. They show up as white spots on the mammogram and can distort results.
  • Wear comfortable clothes that are easy to change out of. You’ll likely need to remove your clothes from the waist up (top and bra) and put on a hospital gown that opens from the front.
  • Don’t wear jewelry. Necklaces and dangly earrings can also distort the mammogram image. It’s best to leave them at home. Ask if it’s OK to wear small earrings or gauges.


How is breast tomosynthesis done?

Having DBT is like having a standard mammogram. The biggest difference is that with DBT, the arm of the machine (X-ray tube) moves in a slow arc around your breast as it takes the X-rays.

  1. The technologist will position you in front of the mammography machine and ask you to place one of your breasts on the platform. They’ll adjust the height of the machine, so it records a clear view of your breast.
  2. Once you’re in place, a plastic plate will slowly lower, squeezing your breast against the platform. You’ll feel pressure at this point. It’s common to feel discomfort, but let the technologist know if the pressure’s painful. Remember that there’s important reasoning behind the discomfort. The compression helps the radiologist get a clearer view of your breast tissue. The compacted tissue also allows for a lower dose of radiation.
  3. The technologist will step away to operate the machine. You’ll need to stay still once the machine’s moving. The technologist may ask you to hold your breath while the machine takes images (only a few seconds).
  4. The X-ray tube will move in an arc-like motion around your breast, taking several low-dose X-rays as it travels.
  5. Once enough images have been taken of one breast, the technologist will repeat the process with your other breast.

How much radiation is used in digital breast tomosynthesis?

The FDA has approved DBT to be used only in combination with mammography. The total radiation dose is just under three times that of a mammogram. While three times may sound like a lot, it’s still a low dose of radiation that’s considered a safe amount of radiation exposure.

Newer tomosynthesis techniques can create 2D images from the data used to make the 3D image. This lowers the radiation exposure so it’s only slightly higher than a standard mammogram.

Mammography, including tomosynthesis, uses the lowest, safest radiation dose possible that still produces a high-quality image for breast cancer detection.

Results and Follow-Up

What type of results do you get, and what do the results mean?

A radiologist will examine the images to check for signs of breast cancer. They may compare the 3D image to your previous mammogram results or the 2D images if they notice a suspicious area. They’ll prepare a report for your provider, who’ll share the results with you.

Depending on the results, you may receive confirmation that you don’t have cancer. You may learn that you need additional tests to check suspicious tissue more closely. You may need an additional mammogram, an ultrasound, MRI or a biopsy. A biopsy is the only way to confirm a cancer diagnosis.

When should I know the results of the test?

You’ll likely get results within a few days, but it may take longer. Before leaving the testing facility, ask about how you’ll receive results and when you should expect them.

Additional Details

Is tomosynthesis better than mammograms?

Tomosynthesis produces a more detailed image of your breast than a standard mammogram. It’s better at detecting cancer and reducing false-positive results in dense breast tissue. Still, research is ongoing about whether 3D mammograms are better than 2D mammograms when it comes to breast cancer screening in general.

Follow your healthcare provider’s recommendations on which breast imaging procedures you need based on your medical history and breast tissue.

Is tomosynthesis the same as a 3D mammogram?

Yes. Tomosynthesis, breast tomosynthesis, digital breast tomosynthesis and 3D mammograms are all the same imaging procedures.

Is tomosynthesis better for dense breasts?

Yes. It provides a more detailed image of your breast, making it easier for a radiologist to tell the difference between dense breast tissue and cancer.

A note from Cleveland Clinic

Digital breast tomosynthesis (DBT) may be the best option for detecting breast cancer if you have dense breast tissue. If you’re due for a mammogram, ask your healthcare provider whether tomosynthesis will be part of the procedure. Depending on your health, a standard mammogram may be enough for breast cancer detection. In some cases, tomosynthesis may be more likely to detect cancer or eliminate the stress of a false-positive result. Don’t hesitate to ask for details about the procedure, including why it is (or isn’t) right for you.

Medically Reviewed

Last reviewed on 10/04/2022.

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