What Is Tomosynthesis (3D mammography)?

Tomosynthesis or “3D” mammography is a new type of digital x-ray mammogram which creates 2D and 3D-like pictures of the breasts. This tool improves the ability of mammography to detect early breast cancers, and decreases the number of women “called back” for additional tests for findings that are not cancers.  During a “3D” exam, an X-ray arm sweeps in a slight arc over your breast, taking multiple low dose x-ray images. Then, a computer produces synthetic 2D and “3D” images of your breast tissue. The images include thin one millimeter slices, enabling the radiologist to scroll through images of the entire breast like flipping through pages of a book, and providing more detail than previously possible. The “3D” images reduce the overlap of breast tissue, and make it possible for a radiologist to better see through your breast tissue on the mammogram.

Hologic Selenia Dimensions with 3D Tomosynthesis

gallery/hologic-3d-mammography
Why is there a need for tomosynthesis breast exams? What are the benefits?

With conventional digital mammography, the radiologist is viewing the tissues of your breast overlapping on flat images. This tissue overlap can sometimes make cancers hard to detect. Also, overlap can sometimes create areas that appear abnormal, but require that you be “called back” for additional tests to determine that cancer is not present (so-called false positives). Tomosynthesis or “3D” mammography directly addresses the current limitations of standard 2D mammography. Multiple studies have shown that “3D” mammography increases the detection of breast cancer by approximately 25%, and decreases the number of false positive call backs by approximately 15%.

What should I expect during the 3D mammography exam?


Having a “3D” mammogram is similar to a having conventional digital mammogram, including the amount of compression of the breasts and the time in compression. The main difference is that the X-ray arm sweeps in a slight arc over your breasts.

Why is compression important in mammography?
  • Decreases radiation dose
  • Separates glandular tissue
  • Decreases superimposition of tissue
  • Improves resolution or clarity of the image
  • Increases contrast to visualize subtle differences in tissue
  • Reduces scatter radiation
Who can have a 3D mammography exam?

It is approved for all women who would be undergoing a standard mammogram, in both the screening and diagnostic settings.

What is the difference between a screening and diagnostic mammogram?

A screening mammogram is done in women who have no breast signs symptoms. A diagnostic mammogram is done in women who have been “called back” from a screening mammogram, or who have a clinical breast symptom such as a lump.