What Is Tomosynthesis for Breast Cancer Diagnosis?

Medically Reviewed by Melinda Ratini, MS, DO on July 02, 2024
3 min read

If you’re getting checked for breast cancer, you may have the option of digital tomosynthesis. Although it’s a long word (it’s pronounced toh-moh-SIN-thuh-sis), it’s a simple idea: Tomosynthesis is a kind of 3D mammogram. It uses 3-dimensional imaging used to look for breast cancers.

In this exam, an X-ray tube moves in an arc around the breast tissue, taking multiple images of the breast from different angles. The information is used to put together 3D images of the layers of breast tissue. Early research suggests that digital tomosynthesis could make it easier to find breast cancers in dense tissue and improve the accuracy of the test.

Mammograms are 2-dimensional, taking two images of the breast: top to bottom and a side-to-side view from an angle. Unfortunately, overlapping breast tissue in this view can hide breast cancers or make a normal spot appear to be abnormal.

Tomosynthesis takes multiple pictures from several angles: 11 images during a 7-second exam.

Tomosynthesis results in fewer false alarms, since the test produces more pictures. A questionable spot on a mammogram may be dismissed as normal breast tissue when you get a better look at it. This can cut down on anxiety in people who may have to repeat tests if the radiologist thinks they’ve spotted a possible cancer, and it also means fewer follow-up tests are needed.

Tomosynthesis finds slightly more cancers than mammograms alone. Research shows that tomosynthesis combined with a mammogram detects about one more cancer per 1,000 women screened.

There may be a modest increase in radiation delivered to the breast in this test versus mammography alone, but experts feel this shouldn’t deter women from opting for this kind of testing.

Preparation for tomosynthesis is like getting ready for a mammogram: Don’t use deodorant, talc, oils, or lotions on your upper body before the exam. You’ll have to take off any above-the-waist clothing and jewelry, and you’ll put on a robe.

During the exam, you’ll stand in front of a mammography X-ray machine and the technologist will put your breast between the two plates, where it will be compressed. (This will probably be uncomfortable, but the X-ray only lasts a few seconds.) You’ll be asked to be still and hold your breath while the X-ray is done. During the X-ray, a special tube will rotate around your breast to take images. Once the test is complete, compression will be released.

Tomosynthesis costs more than a traditional mammogram due to the equipment required and the time involved in interpreting the results. That said, research has found that tomosynthesis screens more effectively for breast cancer, with fewer false positives and higher true negatives than mammograms. And the difference isn’t enormous: In one study, average screening costs were only about $60 higher.

While Medicare covers any additional fees that come with tomosynthesis, some private insurers don’t cover it. In some cases, even if insurance is supposed to cover tomosynthesis, it may apply the charge to your deductible, or it may cover the mammogram but not the tomosynthesis. Before undergoing the test, check with the facility and your insurer so you understand the costs involved.

Keep in mind, tomosynthesis cannot be used to diagnose breast cancer by itself. It’s a screening test used to look for potential tumors. Only a biopsy -- taking a sample of breast cells for testing -- can be used to diagnose breast cancer.