Digital tomosynthesis creates a three-dimensional picture of the breast using x-rays. Several low-dose images from different angles around the breast are used to create the final 3-D picture.
A mammogram creates a two-dimensional image of the breast from two x-ray images of each breast.
Digital tomosynthesis is approved by the U.S. Food and Drug Administration, but is not yet considered the standard of care for breast cancer screening. Because it is relatively new, it is available at a limited number of hospitals.
A study has found that when radiologists looked at digital tomosynthesis images along with digital mammogram images, they were more accurate and had lower false positive recall rates compared to radiologists who looked only at digital mammograms.
A false positive is an abnormal area that looks like cancer on a mammogram, but turns out to be normal. Besides worrying about being diagnosed with breast cancer, a false positive means more tests and follow-up visits, which can be stressful.
The research was published online on Nov. 20, 2012 by Radiology. Read the abstract of “Assessing Radiologist Performance Using Combined Digital Mammography and Breast Tomosynthesis Compared with Digital Mammography Alone: Results of a Multicenter, Multireader Trial.”
The research was made up of two studies. In the first study, 12 radiologists looked at breast images from 312 women. In the second study, 15 radiologists looked at breast images from 310 women.
All the radiologists had more accurate diagnoses when they looked at both digital mammograms and digital tomosynthesis compared to looking only at digital mammograms:
- radiologists were about 11% more accurate in correctly identifying any cancer in the breast in study one
- radiologists were about 16% more accurate in correctly identifying any cancer in the breast in study two
Adding digital tomosynthesis to digital mammograms also reduced the number of false positives found by all the radiologists:
- false positive recall rates dropped by nearly 39% in study one and by about 17% in study two
While the results of this small study are very promising, more research needs to be done before digital tomosynthesis becomes part of routine breast cancer screening. Because it is another imaging test, digital tomosynthesis exposes women to additional radiation. Researchers are looking at ways to replace a standard mammogram image with one created from digital tomosynthesis images to reduce radiation exposure.
Visit the Breastcancer.org Digital Tomosynthesis page to learn more about how the test is done and how it’s different from a mammogram.