Tomosynthesis is a type of mammography that some hospitals now use. It helps screen for breast cancer and may provide more accurate information than a mammogram.

Standard mammograms and tomosynthesis both use X-rays to create an image of the breast, but while the image from a mammogram is 2D, the image from tomosynthesis is 3D.

Breast cancer is a common type of cancer. In the United States, approximately 1 in 8 women and 1 in 833 men develop it in their lifetime.

Effective screening and treatment often make it possible to detect and remove cancer before it spreads. Today, a person who receives a diagnosis of breast cancer in its earliest stage is 99% as likely to live for at least the next 5 years as someone who does not have the disease.

Below, we explain how tomosythesis, also called digital breast tomosynthesis, differs from a standard mammogram, and why receiving breast cancer screening is crucial.

Tomosynthesis scan showing breast cancer growthShare on Pinterest
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The key difference concerns the dimensions of the image that the scan produces. For a standard 2D mammogram, the healthcare professional takes X-rays of each breast from two angles: from top to bottom and from side to side.

A healthcare professional using tomosynthesis takes X-rays of each breast from many angles to produce a 3D image.

Below, we describe each screening technique in more detail.


A mammogram provides an X-ray image of the breast. It can show cancerous growths that are too small to feel, when there are no other signs or symptoms.

A mammogram can show a lump, but it cannot confirm the type of lump. Determining whether it is cancerous or benign requires additional testing, such as more imaging or a biopsy. Sometimes, doctors recommend combining a 2D mammogram with 3D tomosynthesis for a better image.


Because it produces a 3D image rather than a flat one, tomosynthesis give more accurate information about changes in the breast, including whether they warrant further evaluation.

The Food and Drug Administration (FDA) approved tomosynthesis for breast screening in 2011, and research shows that radiologists are highly satisfied with it. But because tomosynthesis is a relatively new technique, confirming its usefulness requires further research.

Because tomosynthesis it is not yet considered a standard screening method, some insurers may not cover it, which restricts access for many patients. Further research into its efficacy may lead to full insurance coverage in the future.

Tomosynthesis is a type of mammography, but the procedure and resulting image are different.

A person’s experience

During both types of screening, a technologist positions each breast on the plate of the mammography machine. They then lower the top plate of the machine to compress the breast while the machine takes a image.

The compression only lasts for a few seconds, but it can be uncomfortable.

Taking the image

During tomosynthesis, the X-ray tube moves in an arc around the breast. Over roughly 7 seconds, the machine takes about 11 images of the breast from different angles. It then transmits the information to a computer, which assembles the data to produce 3D images of the breast.

Interpreting the images

A 2D mammogram can show overlapping areas of breast tissue that resemble a lump or mass. This may lead to a false-positive result.

Because it uses images from multiple angles, tomosynthesis gives a more accurate picture of any changes to breast tissue.

Tomosynthesis may improve breast cancer detection rates because it produces clearer images.

A 2016 review confirms that it is more sensitive to changes than 2D mammography, more likely to provide a clear result the first time, and less likely to produce false-positive results.

Several studies have found that using tomosynthesis and standard mamograms together increases cancer detection rates, compared to using standard mammograms alone. One study found an increased cancer detection rate of more than 42%.

Another found that tomosynthesis combined with mammograms led to the detection of 90% more cancer cases in people who had previously had just standard mammograms.

While there is a need for further studies, tomosynthesis may:

  • enable doctors to identify tumors that standard mammograms do not show
  • reduce the likelihood of false-positive results and the need for subsequent testing
  • detect tumors in dense breast tissue that 2D mammography may not show

Below are some possible disadvantages of tomosynthesis:

  • It can take longer to interpret the images.
  • It is more costly than standard mammography.
  • Finding a nearby facility that offers it may be difficult.
  • It delivers a higher radiation dose than standard mammography.

Overall, further investigations into the risks and potential benefits are necessary.

There are different ways to screen for breast cancer, and doctors often combine methods for a more accurate result.

These screening methods include:

  • Clinical breast examination: A doctor examines the breasts.
  • Ultrasound: This imaging technique can give more information about masses that a mammogram or physical examination detects.
  • MRI scan: This can help a doctor diagnose and assess a mass after surgery or radiation therapy. Doctors also use MRIs to screen for cancer in some people with a high risk.
  • Thermography: This reveals skin temperature changes that could indicate a tumor. Medical professionals may use it alongside a standard mammogram and tomosynthesis, but not as a substitute for either.
  • BRCA testing: This can show whether a person carries the BRCA1 or BRCA2 gene mutations. Either can indicate a higher risk of breast cancer.

For now, 2D mammography remains the gold standard for breast cancer screening.

Early detection and treatment of breast cancer are the most important ways to improve the outlook.

The American Cancer Society recommends the following screening frequency for women aged 40 and older.

AgeScreening frequency
40–44Yearly screening is optional.
45–54Screen for breast cancer every year.
55 and olderScreen for breast cancer either annually or every other year.

These are the recommendations for people who are in good health and expected to live for at least 10 more years.

Other organizations, such as the American College of Physicians, have different recommendations.

A person should speak with a doctor about the advantages and disadvantages of screening. Doctors can help each person arrive at the decision that best meets their needs.

Screening aims to detect:

  • calcium deposits in milk ducts and tissues
  • lumps or masses
  • asymmetric areas
  • dense areas in one breast or one area of the breast
  • new dense areas or any other unusual changes in breast tissue

The outlook for people with breast cancer has improved dramatically over the last few decades, and the likelihood of survival is far higher than it was in the past.

Tomosynthesis is a type of mammography that provides 3D rather than 2D images. The National Cancer Institute warns that insurance companies may not reimburse the costs of this screening because, “Some professional groups consider it investigational.” This highlights the need for further studies.

Currently, this lack of insurance coverage for a technique that provides more accurate imaging may contribute to disparities in health outcomes.

For now, the additional cost and challenges of accessing tomosynthesis may not make it worthwhile, when compared with a standard mammogram.

Here, learn why we need new breast cancer screening guidelines for Black women.