What is 3D Mammogram Breast Screening?

3d mammogram what when and why

Time for your regular mammogram screening? Why a 3D mammogram might be the right choice for you.

A mammogram is a type of X-ray with a low dose of concentrated radiation that monitors changes in breast tissue and is used in breast cancer screening. Mammograms are an excellent preventative measure, often detecting signs of cancer very early, before other symptoms arise. The U.S. Preventative Services Task Force (USPSTF) draft recommends that all women should begin regular mammogram screenings every other year at age 40.

In recent years, 3D mammograms have become available. Also called digital breast tomosynthesis (DBT), 3D mammograms are more accurate than traditional digital mammograms when it comes to diagnosing the earliest signs of breast cancer, especially in dense breasts. In this article, we’ll examine:

  • What a 3D mammogram is and how it differs from a traditional mammogram
  • When it makes sense to get 3D mammogram
  • How effective 3D mammograms are at screening for breast cancer
  • How to prepare for a 3D mammogram and understand your results

What is a 3D mammogram?

A mammogram is an X-ray that uses a very low radiation dose to examine breast tissue. These X-ray images can reveal any abnormal changes before they can be felt in a traditional breast exam. Regular 2D mammograms take two images, one each from the top and the side.

In a 3D mammogram, the X-ray moves in an arc over the breast, taking multiple pictures of the breast from several different angles. Those multiple images or slices, are combined together, providing a more complete view of the breast and making it easier to spot any irregularities.

3D mammograms are highly effective screening mammograms. A 2023 study of more than 1 million women showed that 3D mammograms led both to a higher rate of cancer detection and a lower rate of recalls for further imaging.

3D mammogram example showing multiple 2D image slices

A simplified example of how a 3D mammogram image is built using many image slices taken at different angles, sourced from the National Cancer Institute via National Institutes of Health Image Gallery.

What is the difference between a 3D mammogram and a traditional mammogram?

A traditional 2D mammogram provides 2 images of each breast. 3D mammograms provide hundreds of thinly sliced images. Those slices are brought together to create a highly detailed 3D view of the whole breast.

Mammograms are also the only way to assess breast density. 3D mammograms are more effective for dense breasts because physicians can see the dense areas from several different angles.

A traditional 2D mammogram presents two overlapping images. That overlap can obscure potential abnormalities, causing them to be missed at the earliest stages. It’s also possible for overlapping tissue to make benign spots look abnormal, which then requires you to have further imaging done for clarification.

Are 3D mammograms painful?

3D mammograms feel like 2D mammograms. In both, your breast is compressed by a clear plate against the X-ray platform and pressure is applied while the X-ray images are taken. That pressure can feel uncomfortable, but it’s necessary to improve image clarity.

3D mammograms take a little longer than traditional mammograms, so the pressure will last several more seconds. It’s important to keep the technologist appraised of your level of discomfort.

4 reasons to get a 3D mammogram

There are several reasons someone may choose the 3D option over traditional digital 2D mammograms, including:

  1. Increased accuracy. 3D mammograms detect the earliest signs of cancer at a higher rate than regular mammograms.
  2. Reduced need for follow-up imaging. The higher level of image clarity means fewer patients require follow-up scans.
  3. Effective for dense breasts. The fibrous nature of dense breasts makes it harder to see the early warning signs of cancer with a traditional 2D mammogram.
  4. Follow-up diagnostic screening. If you need a second scan, a 3D mammogram will provide more fine detail than a traditional mammogram.

What is breast density and how is it measured?

Breast density refers to the type and composition of your breast tissue. Dense breasts contain more fibrous and glandular tissue than fatty tissue. Dense breasts are both normal and common, but increased density can obscure images on a regular mammogram. Both cancer and dense breast tissue look white in mammogram images.

Radiologists determine your breast density with mammograms. There are 4 categories:

  • Category A have less than 25% dense tissue.
  • Category B breasts have scattered areas of 25-50% dense tissue.
  • Category C breasts are heterogeneously dense, with 50-75% dense tissue.
  • Category D breasts are extremely dense, with 75%+ dense tissue.

Breast density is a risk factor for breast cancer. Women with category D density are 4-6 times more likely to develop cancer than people with breasts in the least dense category (less than 25% dense tissue).

Several factors affect breast density, including:

  • Age. Breast density often decreases with age. 56% of women in their 40s have dense breasts compared to only 27% of women in their 60s. Breast density also tends to decrease after menopause.
  • Size. There’s a strong correlation between small breast size and high density.
  • Ethnicity. Women of Asian descent tend to have higher breast density than other ethnicities.
  • Heredity. You can genetically inherit dense breasts.
  • Pregnancy or breastfeeding. Your breasts become temporarily denser during these periods.
  • Drug effects. Cancer drugs reduce breast density, while hormone replacements can increase it.

How effective are 3D mammograms for breast cancer screening?

According to this 2023 study, 3D mammograms detect cancer in 5.3 out of 1000 cases, whereas traditional mammograms found cancer in 4.5 out of 1000. That’s a significant difference when it comes to early detection and treatment. Studies have also shown that 3D mammograms detect more kinds of cancer than regular 2D mammograms.

How often should you get a mammogram?

Medical bodies suggest different starting ages, but in 2023, the USPSTF issued a draft recommendation that women start regular screening mammograms every other year beginning at age 40. At 55, you can scan every year in the U.S.

Should you have a family health history of breast cancer, you should begin your screening sooner, and consider both mammograms and MRIs. Always discuss your risk factors with your physician so you can explore the best scan options for your particular needs.

Pros and cons of 3D mammograms

As with all medical procedures, there are pros and cons when getting a 3D mammogram.


  • Can detect more cancers
  • Are more accurate when scanning dense breasts
  • Provide a more complete picture of overall breast composition
  • Result in fewer callbacks for further imaging


  • Not every imaging clinic offers 3D mammograms
  • Sometimes there is an extra cost that may not be covered by insurance
  • Slightly longer exposure to low-dose radiation.

How to prepare for a 3D mammogram

While a 3D mammogram only requires a short appointment, there are some steps you can take to prepare in advance:

  • Bring your requisition with you. The requisition has important information for the imaging clinic or hospital.
  • Use the same clinic. Whenever possible, have your mammograms at the same clinic each time. This will make it easier for the radiologist to compare images. Or speak to your doctor to get images from any previous mammograms to bring with you.
  • Schedule your mammogram when your breasts are least sensitive. Your breasts may feel tender leading up to or during your menstrual cycle, so avoid making your mammogram appointment during these times. Many prefer to avoid 7-10 days before their period.
  • Avoid deodorant or antiperspirant, and lotions. Don’t apply deodorant or antiperspirant on the day of your mammogram appointment, and make sure to wipe off any deodorant residue since the mammogram can pick up the aluminum. Also, avoid wearing powder or body lotion under your arms or your breasts.
  • Remove long earrings or necklaces. It’s best to avoid wearing jewelry to your appointment because the metal can interfere with your images.
  • Wear a top and bottom, rather than a dress. You will be asked to remove your top and bra during your mammogram, so wearing pants or a skirt may make you more comfortable during your appointment.
  • Reduce caffeine intake. Caffeine can make breast tissue more tender, so try to avoid—or limit—caffeine intake for 4-5 days before your appointment.
  • Let the clinic know if you have implants. Breast implants require modifications to the mammogram process, so your appointment may take longer. Also let the technologist know about any changes or sensitive areas, or if you are breastfeeding.
  • Obtain prior mammogram imaging. Speak with your doctor to get imaging from previous mammogram clinics so that you can bring the imaging to your new appointment or request that your doctor send the imaging to the clinic prior to your appointment. PocketHealth helps you keep your medical imaging securely organized together, so you can bring them to your appointments yourself or share them at referral appointments. Having all your mammogram imaging in one place lets you easily monitor different imaging results over time.

The imaging clinic or department will provide wipes to clean up after your screening, but you may wish to pack deodorant or antiperspirant to bring with you to wear after the appointment. Also, if you are concerned about pain during your appointment, ask your doctor if over-the-counter medication can help reduce discomfort.

Questions to ask during and after your 3D mammogram screening

Your mammogram technician cannot answer questions about the results of your 3D mammogram. But you can ask questions about the process and procedure, like:

  • What can I expect during this appointment, and how long will it last?
  • What equipment are you using?
  • How do I let you know if the pressure is too much?
  • When will my physician get the results?
  • How can I access my images and report?

The technologist will send your images to the radiologist, who will compile and interpret the images before sending the full report to your physician. At your follow-up appointment, you can ask more specific questions, such as:

  • Have there been any changes since my last mammogram?
  • Are there any signs of cancer?
  • Are there any other abnormalities I should be aware of?
  • What is my breast density category?
  • Do I need any additional imaging or tests?
  • When should I schedule my next 3D mammogram?

How to access your 3D mammogram imaging and report

When your 3D mammogram is complete, you can access your images and report through PocketHealth, often before your follow-up appointment with your primary practitioner. Access your records here.

PocketHealth allows you to access, view and store your medical images and health information all in one secure location. You can also use PocketHealth to share images.

Mammography reports are technical documents with complex terminology. PocketHealth Report Reader makes it easy to understand terms in your mammogram report and also highlights any follow-up recommendations, so you can be confident and informed when speaking to your doctor at your mammogram follow-up appointment.

Understanding your 3D mammogram results

Doctors use mammograms to check for changes and abnormalities in breast tissue. Not all of these are signs of cancer, indeed, many are fairly common. The main changes mammograms scan for are:

  • Asymmetries are areas that have a different shape than the surrounding breast tissue pattern. There are several types of asymmetry—in most cases, they do not represent cancer.
  • Calcifications are tiny deposits of calcium. Larger macrocalcifications are generally due to aging and don’t typically require a biopsy. Smaller microcalcifications are more of a concern but do not in themselves indicate cancer.
  • Distortions can be due to past injury or breast position on the X-ray table. But sudden significant distortion will often require a follow-up diagnostic screening.
  • Masses are an abnormal sector with distinct edges that look different from the surrounding breast tissue. Masses might indicate cancer, but they can also be evidence of fluid-filled cysts or non-cancerous fibroadenomas.

In a normal breast image, the background will be black while the breast tissue shows up in shades of gray. Dense tissue and glands will be white, whereas abnormalities like the ones listed above will have unique appearances. For example:

  • Calcifications will be white flecks of varying size.
  • Cysts will have thin walls and fluid-filled interiors.
  • Cancer presents as a concentrated white area, like a tumor. However, most breast tumors are non-cancerous.

Some of these abnormalities will suggest further testing, which might include another mammogram or a biopsy.
Doctors use a standard vocabulary to describe mammogram results, called the Breast Imaging Reporting and Data System (BI-RADS). BI-RADS has 7 numbered categories.

  • Category 0: scan was incomplete or unclear, and you will need further testing, which might include another mammogram for comparison.
  • Category 1: a normal test result, considered ‘negative’ in that nothing abnormal or new was detected.
  • Category 2: also a negative test result, which includes some sort of non-cancerous finding like a benign calcification.
  • Category 3: a possibly benign scan but one which reveals a finding that suggests a follow-up image be taken, generally within the year.
  • Category 4: a suspicious finding which is not confirmed to be cancer. A biopsy is often recommended.
  • Category 5: these findings typically suggest cancer: a biopsy is strongly recommended.
  • Category 6: this category is only used for findings taken after cancer has already been proven.

An additional scan to support your breast health

Regular mammograms are vital for breast cancer detection and prevention. 3D mammograms take many more images than traditional 2D mammograms, which are then combined to create a highly detailed view of breast composition and health.

Mammograms of all types have life-saving potential since they can detect signs of breast cancer before you can feel them. Discuss 3D mammography with your physician to see if it’s the right choice for you. It’s important to stay both informed and proactive when it comes to maintaining your breast health.

How PocketHealth works

Learn more about how to use PocketHealth to access and share your 3D mammogram records.

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