Digital Breast Tomosynthesis (3D Mammography)
What is breast tomosynthesis?
Breast tomosynthesis, or 3D mammography, is a technique using low dose xrays to produce a three dimensional picture of the breast. Standard, or 2D mammograms, consist of one picture of the breast, from 2 different positions. Top to bottom and side to side. To do this, the breast tissue is compressed (smushed), which results in a picture of overlapping breast tissue. This overlapping breast tissue can make the 2D images difficult to interpret.
During a 3D mammogram, the machine moves around the breast, taking picture “slices” through the breast. These can be viewed as individual pictures or combined to make a 3D image of the breast, minimizing the overlapping of breast tissue. This often clarifies whether something is truly abnormal, and can allow the radiologist to see abnormalities that would be hard or impossible to see otherwise.
How is the test performed?
The test is done using a digital mammography machine- the same machine used for traditional mammograms, though not all of these machines have 3D capability. The breast tissue is compressed between clear plastic paddles as in traditional mammography. The “camera” swings around the breast in an arc, taking multiple pictures as it goes around. The machine produces the 3D images, as well as a 2D image for comparison. With the newest technology, the 2D images can be reconstructed from the tomosynthesis 3D images, decreasing the xray dose. Compression will last for just a few seconds longer than for a standard mammogram, but most patients will likely not notice a difference.
Who should get breast tomosynthesis?
Everyone who is a candidate for 2D mammography is also a candidate for tomosynthesis. Patients with dense breast tissue may benefit more from the added modality than those with more fatty breast tissue, but even fatty breasts are better evaluated with tomosynthesis.
Is there more radiation exposure in a 3D mammogram?
With older equipment, a patient must have 2D pictures taken AND 3D pictures, which essentially doubles the amount of radiation received. However, newer machines are able to create the 2D images from the 3D images. This is sometimes called “synthetic” technology. With this technology, only one set of pictures is taken and the amount of radiation is essentially the same as with a traditional 2D mammogram. Even for studies where the 2D and 3D images are both obtained, the total dose of radiation is still below the limit under the Mammography Quality Standards Act (MQSA) set forth by the FDA.
How do I get a 3D mammogram?
Your healthcare provider can order it, or you can request it at the time of the study. Not every facility offers this technology, so you would need to ask your mammogram center if they have 3D mammogram available.
Does the test cost more and will insurance cover it?
3D mammogram does cost more than traditional 2D mammogram. Research has shown that despite higher costs of the test, it results in less expense in the long run due to fewer callbacks, follow up screening, and biopsies.
Many insurance companies, including Medicare, do cover the additional costs. You should check with your insurance carrier to see if you will be covered.
How is 3D mammography better than 2D?
3D mammography reduces the number of women called back for unnecessary screenings and biopsies due to false alarms by up to 40%, which reduces anxiety and health care costs. In addition, 3D mammography finds up to 40% more invasive breast cancers than a traditional mammogram. Invasive cancers are more likely to spread or cause death. This all adds up to better and earlier detection of breast cancer, resulting in more lives saved.
Resources for more information:
Radiological Society of North America - Breast Tomosynthesis
Breastcancer.org - Digital Tomosynthesis