A new state law this year requires commercial insurers to cover 3D mammograms, a more advanced — and expensive — form of screening for breast cancer than the standard 2D version.
Dr. Douglas Baker, a diagnostic radiologist with Texas Health Dallas, says 3D mammograms allow doctors to find breast cancer sooner and smaller in size, lessening the need for extensive treatment and the cost for patients.
How 3D mammography works: Instead of just acquiring one image in each direction, it acquires a series of multiple images over an arc of 25 to 40 degrees, and then the computer synthesizes those images into a 3D reconstructed set. The radiologist at a separate workstation reviews these images at slices of one millimeter in thickness. So instead of having one image to look at, we have 50 to 100 images that we view in a little semi-loop. They hopefully will identify small lesions that otherwise would be obscured normal overlapping tissue.
Why 2D mammography is an option: Not every facility has 3D mammography available. Hopefully, in the coming years that will change. Where 3D mammograms are available, they’re done in conjunction with a 2D mammogram. The patient is positioned the same as they are for a 2D mammogram, and the machine acquires both the 2D and 3D images in one compression. It doesn’t require any extra time. It doesn’t require any extra positioning to do the 3D mammogram. It’s all done at the same time as the 2D is.
Watch a video on 3D mammography from Texas Health Resources
Advantages of 3D mammograms:
- Fewer “callbacks”: Traditionally, with 2D about 10 percent of patients will be called back for additional imaging based on the original screening mammogram. Most of those turn out to be normal overlapping fibroglandular tissue or something else that’s benign. With the 3D mammogram, we’re hoping for a 30-to-50-percent decrease in the number of callbacks because we’re getting better images to start with.
- Less obstructed image: Dense breast tissue has been the Achilles heel of mammography. It shows up as white on a mammogram, which is the same density as a small cancer. Because of that, normal tissue could block our view of an early breast cancer. Now with a 3D, we can find things at a very early, very small stage, years before a patient would ever know there was anything wrong.
On longer radiation exposure with 3D: A computer can reconstruct 3D images into a 2D version. But if you do the 2D and the 3D, which is still very commonly done, the radiation does increase, but it’s still considered a very safe level. It should not be a concern to women undergoing mammography testing.
The interview has been edited for clarity and length.