With digital breast tomosynthesis (DBT)—also known as 3D mammography—radiologists can view breast images in slices, which essentially allows them to see through tissue layers, making it less likely they’ll miss an early sign of cancer.  

“Instead of judging a book by its cover, as is the case with 2D mammography, DBT allows you to read all the pages—or slices—to understand the real story,” says Melissa Durand, MD, an associate professor of Radiology & Biomedical Imaging at Yale Cancer Center.  

Compared to 2D mammograms, DBT technology also makes it easier for radiologists to detect breast cancer that is masked by overlapping fibroglandular tissue. “And that's why this technology has rapidly become an essential imaging tool that enhances a doctor's ability to detect early breast cancer,” says Dr. Durand. “With breast cancer, earlier detection leads to earlier treatment—when the cancer is more easily treated—and increases the chances of being cured.” 

Mammography, a procedure that uses X-rays to create images of breast tissue, is commonly used to screen for and diagnose breast cancer. Radiologists closely examine these images to check for abnormalities in breast tissue. About 10 to 15% of abnormalities found during screening mammograms are cancerous tumors. The rest—about 85 to 90%—are from noncancerous causes, such as calcifications (calcium deposits), cysts, or benign (noncancerous) tumors.  

Conventional mammography produces a 2D image of breast tissue. With DBT mammography, a special machine takes multiple X-rays of breast tissue from various angles. A computer then combines these images into a number of 1-millimeter slices of breast tissue that radiologists can examine to look for signs of breast cancer.

Studies have found that DBT mammography significantly increases breast cancer detection rates and reduces recalls for further testing in comparison to 2D mammography. And that means less unnecessary worry. For women with dense breasts, DBT mammography may be able to detect some cancers that are not detected by conventional 2D mammography.

The experience of having DBT mammogram feels the same as having a 2D one. You arrive and change into a dressing gown. A radiology technician escorts you to a private mammography room with the DBT mammography machine. (It looks the same as a conventional 2D mammography machine.)   

The technician helps you position your body. The breast is supported by a tray while a flexible plastic plate is gently lowered to press against the breast.

The machine then takes a series of low-radiation dose X-ray images at different angles, all within just a few seconds. The process is repeated for the other breast. In all, the appointment takes about 30 minutes.

The radiologist reviews the images and sends a complete report with the results to you and your doctor. 

Talk to your health care provider about when you should begin having screening mammograms.

The U.S. Preventive Services Task Force recommends that women between ages 40 and 74 who are at average risk for breast cancer get a screening mammogram every two years. Women at higher-than-average risk for breast cancer, such as those who have inherited a BRCA gene mutation or have a strong family history of breast cancer, should talk to their health care provider about starting regular breast cancer screening at a younger age and which screening tests are most appropriate for them.

There are two different types: screening and diagnostic DBT mammograms.  

• Screening DBT mammograms: Screening mammograms are used to check the whole breast for breast cancer before it causes symptoms or a lump can be felt in the breast. The goal of screening is to catch breast cancer at an early stage when it’s easier to treat. Studies have shown that screening mammograms can reduce mortality from breast cancer in women between 40 and 74 years of age. Screening mammograms are typically performed every year or two in women at average risk for breast cancer starting at age 40.
  
  Women whose screening mammogram indicates they have dense breasts can also choose to schedule additional screening tests, in particular a breast ultrasound or a magnetic resonance imaging (MRI) scan. Rest assured, dense breasts are perfectly normal (and half of all women who undergo screening mammography have them). But dense breast tissue makes it more difficult for radiologists to detect cancer using mammography, so an ultrasound or MRI gives doctors another way to check for cancerous lesions. 
  
  Depending on what the radiologist finds, a breast biopsy may be needed to obtain a tissue sample to be sent to a pathologist for review. These steps are taken to diagnose or rule out breast cancer.
• Diagnostic DBT mammograms: If a patient has breast cancer symptoms, such as breast pain, nipple discharge, or feels a lump in a breast—or if a screening mammogram has detected an abnormality—an additional mammogram, known as a diagnostic mammogram, may be necessary. This type of mammogram takes images focused only on the area of concern.

“The breast radiologists at Yale were among the earliest adopters of DBT technology in the world, so we have some of the highest levels of experience with this type of mammography,” says Dr. Durand. “We have also had additional breast-specific training in all aspects of breast imaging, from reading screening and diagnostic mammograms, ultrasounds, and MRIs, to image-guided procedures. Taken together, we offer patients the best chance at early detection of breast cancer, which is the key to having the best patient outcomes.”