Breasts are made up of fatty tissue, fibrous tissue, and glandular tissue. Someone is said to have dense breast tissue (as seen on a mammogram) when they have more glandular and fibrous tissue and less fatty tissue. A number of factors can affect breast density, such as age, menopausal status, the use of drugs (such as menopausal hormone therapy), pregnancy, and genetics.

People with dense breasts have a slightly greater risk of breast cancer than women with less dense breasts and new laws and recommendations in many states now require physicians to inform a patient if they have dense breasts.

In fact, the Breast Density Notification Act, requires mammography facilities in Pennsylvania to notify people of their breast density. Although the relationship between dense breast tissue and breast cancer is small, it's one that can only be seen through medical imaging – such as a mammogram.

Also, dense breast tissue can make mammograms less accurate. Because dense breast tissue shows up as white on a mammogram, it can be more difficult to spot cancers, which also may look white on a mammogram.

DBT Makes Mammography More Accurate

A revolutionary way to perform mammograms combining traditional mammography with 3D technology, called digital breast tomosynthesis (DBT), allows for more accurate pictures of the breasts and is helpful for women with dense breasts.

“DBT is more accurate – even more accurate than digital mammograms – because it uses traditional X-ray technology to capture images of the breast, while moving along a small arc around the breast to record images at different depths and angles,” said Emily Conant, MD, director of women's imaging at the Hospital of the University of Pennsylvania. “Research has shown that using DBT imaging reduces the number of false-positives and some false-negatives making mammography more accurate.”

Like a traditional mammogram, the breast is compressed for about four to five seconds while a series of low-dose X-rays are taken to capture high-resolution images of the breast. These images are then digitally “stacked” to construct a total 3D image of the breast. This 3D image allows radiologists to scroll through, and “peel apart” the layers of the breast to view the breast tissue at different depths and angles. Radiologists can also magnify images to reveal minute details.

“DBT allows Penn radiologists to manipulate and see parts of the breast that we couldn't before,” Dr. Conant said. “Therefore, we can reduce some unnecessary imaging and stress for some women.

“DBT lets us to see the through some of the density of a breast. For all women, and especially those with dense breasts, we can improve our screening outcomes with DBT.”

Other Advantages of DBT

Women who get their mammograms using DBT technology may find they are called back less often for follow-up visits and additional testing.

New imaging advantages such as DBT and advances in risk assessment are part of a collaborative effort between radiologists, medical oncologists, and surgeons to try to improve breast cancer detection for women.

Technology continues to evolve, but collaborative research across all disciplines at Penn Medicine means patients who come to Penn for their mammograms benefit from the latest medical breakthroughs.

“DBT is just one more step to improving breast care on an individual, personalized basis,” said Dr. Conant. “Combining personal history, genetic testing and new breast images creates a better, overall picture for breast health.”