A 3D mammogram is an imaging test that combines multiple breast X-rays into a 3D picture of the breast. Another name for 3D mammogram is breast tomosynthesis.

A 3D mammogram can help find breast cancer in people who have no symptoms. It also can help find the cause of breast concerns, such as a breast mass, pain and nipple discharge.

Before the 3D mammogram became common, breast cancer screening mammograms used standard machines. Standard mammogram machines make 2D pictures of the breast. These 2D images still have some benefits. So when it's used for breast cancer screening, a 3D mammogram machine makes both 3D and 2D images of the breast. Using these images together for breast cancer screening reduces the need for more imaging later. It also slightly increases the number of cancers found during screening.

Most healthcare facilities in the United States offer 3D mammograms.

Why it's done

A 3D mammogram is a breast cancer screening test that helps find breast cancer in people with no symptoms of the disease. It also can be used to look at breast concerns, such as a breast mass, pain and nipple discharge.

A 3D mammogram differs from a standard mammogram because it makes 3D images. A standard mammogram makes 2D images. Both kinds of images have some benefits. So when a 3D mammogram machine is used for breast cancer screening, the machine makes 3D images and 2D images.

Using 2D and 3D images together for breast cancer screening can:

Reduce the need for follow-up imaging

If a standard mammogram detects something worrying, you might need more imaging tests to take a closer look at it. Being called back for additional imaging can be stressful. It may take extra time and lead to additional costs. A 3D mammogram reduces the need for follow-up imaging.

Improve breast cancer detection in dense breast tissue

A 3D mammogram offers advantages in finding breast cancer in people with dense breast tissue. The 3D image allows doctors to see beyond areas of density.

The breasts are made up of dense breast tissue and fatty breast tissue. Dense breast tissue includes the milk glands, milk ducts and supportive tissue in the breast. Fatty tissue is made of fat cells. A person with dense breast tissue has more dense tissue than fatty tissue.

On a mammogram image, the fatty breast tissue is transparent. It's easy to see through to look for anything concerning. The dense breast tissue looks solid white on the mammogram image. It's hard to see through. Breast cancer, which also looks solid white on a mammogram, could be missed.

Risks

A 3D mammogram is a safe procedure. As with every test, it carries certain risks and limitations, such as:

• The test gives a low level of radiation. A 3D mammogram uses X-rays to create an image of the breast, which exposes you to a low level of radiation.
• The test may find something that turns out to not be cancer. A 3D mammogram may find something worrying that, after additional tests, turns out to not be cancer. This is called a false-positive result. For some people, finding out that there is no cancer feels reassuring. For others, having tests and procedures for no reason feels frustrating.
• The test can't detect all cancers. It's possible for a 3D mammogram to miss an area of cancer. This can happen if the cancer is very small or if it's in an area that's difficult to see.

How you prepare

To prepare for a 3D mammogram:

• Get the test when your breasts are least likely to be tender. If you haven't gone through menopause, that's usually during the week after your menstrual period. Your breasts are most likely to be tender the week before and the week during your period.
• Bring your old mammogram images. If you're going to a new facility for your 3D mammogram, gather any old mammogram images. Bring them with you to your appointment so they can be compared to your new images.
• Don't use deodorant before your mammogram. Avoid using deodorants, antiperspirants, powders, lotions, creams or perfumes under your arms or on your breasts. Metallic particles in powders and deodorants can interfere with the imaging.

What you can expect

At the testing facility, you put on a gown and remove any necklaces and clothing from the waist up. To make this easier, wear a two-piece outfit that day.

For the procedure, you stand in front of an X-ray machine that can do 3D mammograms. The technician places one of your breasts on a platform and raises or lowers the platform to match your height. The technician helps you position your head, arms and torso to allow a clear view of your breast.

Your breast is gradually pressed against the platform by a clear plastic plate. Pressure is applied for a few seconds to spread out the breast tissue. The pressure isn't harmful, but you may find it uncomfortable or even painful. If you have too much discomfort, tell the technician.

Next, the X-ray machine moves above you from one side to the other as it collects images. You may be asked to stand still and hold your breath for a few seconds to minimize movement.

The pressure on your breast is released, and the machine is moved to take an image of your breast from the side. Your breast is positioned against the platform again, and the clear plastic plate is used to apply pressure. The machine takes images again. The process is then repeated on the other breast.

Results

The results of a 3D mammogram are typically available soon after the test is completed. Ask your healthcare professional when you can expect your results.

A computer takes the images collected during a 3D mammogram and forms them into a 3D picture of your breast. The 3D mammogram images can be analyzed as a whole or examined in small fractions for greater detail. For breast cancer screening purposes, the machine also creates standard 2D mammogram images.

A doctor who specializes in interpreting imaging tests examines the images to look for anything worrying. This doctor is called a radiologist. If anything worrying is found, the radiologist may look at your past mammogram images, if they are available. The radiologist decides whether you may need more imaging tests.

Additional tests for breast cancer may include an ultrasound, an MRI or, sometimes, a biopsy to remove suspicious cells for testing in a lab.