A mammogram is an X-ray of breast tissue. It’s used to help detect breast cancer. Traditionally, these images have been taken in 2-D, so they’re flat black-and-white pictures that a doctor examines on a computer screen.

There are also 3-D mammograms available for use with a 2-D mammogram or alone. This test takes multiple photos of the breasts at once from different angles, creating a clearer, more dimensional image. You may also hear this more advanced technology referred to as digital breast tomosynthesis or simply tomo.

More than 200,000 women are diagnosed with breast cancer each year in the United States. Early detection is key to catching the disease before it spreads and improving survival rates. While 2-D mammograms are generally effective at detecting breast cancer, 3-D mammograms may detect some one to two more cancers per 1,000 women.

Other pros of breast tomosynthesis include the following:

  • It’s approved for use by the U.S. Food and Drug Administration.
  • It can be performed at the same time as a 2-D mammogram.
  • It’s better at detecting breast cancer in younger women with dense breast tissue.
  • It produces detailed images that are similar to those you would get with a CT scan.
  • It reduces additional testing appointments (recalls) for areas that aren’t cancerous.
  • When performed alone, it doesn’t expose the body to significantly more radiation than traditional mammography.

Around 50 percent of Breast Cancer Surveillance Consortium facilities offer 3-D mammograms. So this technology isn’t yet readily available to everyone.

Here are some of the other pitfalls:

  • It costs more than 2-D mammography and may or may not be covered by insurance.
  • It takes slightly longer to perform and interpret.
  • When used together with 2-D mammography, exposure to radiation is slightly higher.
  • It’s a relatively new technology, which means that not all risks and benefits have yet been established.
  • It may lead to overdiagnosis or “false recalls.”
  • It’s not available in all locations, so you may need to travel.

Women over age 40 should have a traditional mammogram each year to screen for cancer. The American Cancer Society specifically recommends that women between the ages of 45 and 54 have yearly mammograms, followed by visits every two years until at least age 64. The U.S. Preventive Services Task Force recommends women have mammograms until at least age 74.

What about breast tomosynthesis? This technology may have benefits for women in all age groups. That said, women’s breast tissue after menopause becomes less dense, making tumors easier to spot using 2-D technology. As a result, 3-D mammograms may be especially helpful for younger, premenopausal women who have denser breast tissue.

3-D mammography is more expensive than traditional mammogram, so your insurance may charge you more for this testing. Many insurance policies cover the 2-D test in full as part of preventative care. With breast tomosynthesis, insurance may not cover the costs at all or may charge a copay up to $100.

The good news is that Medicare started covering 3-D testing in 2015. And as of early 2017, five states were considering adding mandatory coverage of digital breast tomosynthesis. The states with proposed bills include Maryland, New Hampshire, New Jersey, New York, and Texas.

If you’re concerned about the costs, contact your medical insurance provider to find out your plan’s specific coverage.

The actual procedure for a 3-D mammogram is very similar to the 2-D experience. In fact, the only difference you may see is that it takes around a minute longer to perform a 3-D test.

In both screenings, your breast is compressed between two plates. The difference is that with 2-D, the images are taken only from the front and side angles. With 3-D, images are taken in what are called “slices” from multiple angles.

What about discomfort? Again, the 2-D and 3-D experiences are much the same. There is no more discomfort associated with the advanced test than the traditional.

In many cases, you may have both 2-D and 3-D tests done together. It may take radiologists longer to interpret results from 3-D mammograms because there are more images to look over.

A growing set of data suggests 3-D mammograms may improve cancer detection rates.

In a study published by The Lancet, researchers examined detection using 2-D mammograms alone versus using both 2-D and 3-D mammograms together. Of 59 cancers detected, 20 were found using both 2-D and 3-D technology. None of these cancers were found using a 2-D test alone.

A follow-up study echoed these findings but cautioned that the combination of 2-D and 3-D mammography may lead to “false-positive recalls.” In other words, while more cancer is detected using a combination of technologies, it may also lead to the potential for overdiagnosis.

Yet another study looked at the amount of time it takes to obtain images and read them for signs of cancer. With 2-D mammograms, the average time was around 3 minutes and 13 seconds. With 3-D mammograms, the average was around 4 minutes and 3 seconds. Interpreting results with 3-D was longer as well: 77 seconds versus 33 seconds. The researchers concluded that this extra time was well worth it. The combination of 2-D and 3-D images improved screening accuracy and resulted in fewer recalls.

Speak with your doctor about 3-D mammograms, especially if you’re premenopausal or suspect you have dense breast tissue. Your insurance provider can explain any associated costs, as well as share locations near you that perform 3-D testing.

Regardless of what method you choose, it’s important to keep up with your annual screenings. Early detection of breast cancer helps catch the disease before it spreads to other parts of the body. Finding cancer earlier also opens up more treatment options and may improve your survival rate by up to 93 percent in the first five years after diagnosis.