Mammograms are low-dose x-rays that expose the breasts to a small amount of radiation.* Mammograms have been used to screen for breast cancer since the 1980s. There are three different types of mammograms:
- Film: 2-Dimensional, known as “analog” has been nearly eliminated in the U.S.A., but is still in use in Europe and some places in Latin America.
- Digital, 2-Dimensional: known as “Full Field Digital Mammogram” (FFDM). Nearly all facilities in the United States have digital mammography.
- Digital, 3D/tomosynthesis: also referred to as “3-Dimensional” or “tomo.” It is a newer technology that is used in over half of the facilities in the United States is also available in Latin America.
How are a 2D and 3D digital mammogram different?
To explain the difference, think of a 2D mammogram like a photograph of a book. The words on each page of the book would have their letters jumbled on top of the words from all the other pages, so it would be very difficult to read any particular word. Any given “word” could be a small mass due to cancer.
Now, to understand a 3D mammogram, imagine the cover and pages of the book are see-through. The 3D mammogram captures images at different angles, which allows thin “slice” images to be made by the computer. These images can then be viewed one at a time–similar to turning pages of a book and being able to read the words on each page.
A 2D mammogram finds about 5 cancers for every 1,000 women who have a mammogram. Another 1-2 cancers will be found per 1,000 women when 3D/tomosynthesis is used. With 3D mammograms, you are also less likely to be called back for more testing. However, in women with extremely dense breasts, studies have shown mixed results as to whether 3D mammograms find more cancers than 2D mammograms.
*The radiation exposure from a mammogram is small and is too low to cause any harm to the breasts.
To learn more about mammograms, including how they work, benefits and things to consider, click here.
Learn More:
- 5 Facts Every Woman Should Know
- Video Series: Let’s Talk About Dense Breasts
- Patient Risk Checklist (print)
- Patient Questions and Answers