If you’re wondering how 3D mammography (also called tomosynthesis) works, we have answers. While the machinery will look much like a traditional mammography machine, you will notice a difference when the images are taken. The upper part of the machine will move in an arc while taking several images of the breast tissue. The latest machines approved for 3D mammography can do a 3D study with the same radiation dose as a conventional 2D mammogram, unlike some earlier versions. This is still a mammogram, and yes, compression is still required.
Computers are used to take the digital data obtained from those multiple mini-exposures and convert it into multiple thin, 1 mm or less slices through the breast tissue. The 3D part is done in the radiologist’s head - no special glasses required! The benefit to the radiologist is that the tissue of the breast can be seen without overlap. Think of trying to look through the pages of a book as a whole, versus looking at one page of a book at a time - this is sort of the difference between a 2D mammogram where all the tissue overlaps versus a 3D mammogram where it can be separated.
So what is gained with 3D mammography? There are two important benefits: first, 3D mammography allows the radiologist to find more cancers. Are we excited to find more cancer? No, but… the benefits of early detection are astounding, skyrocketing survival rates. If we can catch cancer early, we can literally save lives. We don’t dance for joy when we discover cancer, but we dance when we know our patient will live.
The other big benefit is the need for fewer work-up studies, especially diagnostic mammograms following a screening study, because we are able to view the tissue without overlap. The need for additional testing is reduced, thus saving time, cost and anxiety.
While research has shown consistently positive results in the number of cancers found and the reduction in the need for additional testing, the precise role of 3D mammography is still under investigation. Further, most payors are not covering the additional cost of 3D mammography.
More breast cancers are found in women with all breast densities, but those with dense breast tissue will likely benefit the most. Other groups we think will benefit the most include women with a history of breast cancer, family history of breast cancer, women with previous inconclusive mammograms and women with prior breast cysts or lumps.
In short, 3D mammography is proving to be a very valuable tool for breast cancer screening and detection.
Originally published 6/2/15 on mammographykc.com.