3D Mammogram (Digital Breast Tomosynthesis)

What is a 3D mammogram?

A 3D mammogram, also known as digital breast tomosynthesis (DBT), uses a series of two-dimensional images to build a three-dimensional image of the breast.

It can be used:

As a screening tool to detect breast cancer
As a diagnostic tool to further evaluate abnormalities detected in conventional 2D mammograms

The mammogram machine takes multiple low-dose X-ray images of each breast from different angles. The computer software will process these thin slice images to reconstruct into detailed 3D images of the breast.

While mammograms are the best screening tool for breast cancer available today, mammograms do not detect all breast cancers.

3D mammogram (DBT) vs conventional mammography

During a DBT exam, the breast is positioned and compressed the same way as it is for a conventional 2D mammogram.

However, during the DBT exam, the X-ray tube moves in an arc over the breast, taking multiple images of the breast as it moves.

Many studies have shown DBT's superiority over 2D mammography since it was approved by FDA in 2011, particularly in terms of the cancer detection rate and the recall rate, or the rate at which patients are called back for additional imaging.

Why do you need a 3D mammogram?

A 3D mammogram is often used for breast cancer screening. Even if you have no noticeable symptoms of breast cancer, you should still get screened regularly so that any potential problems can be detected and treated early.

According to the Health Promotion Board in Singapore, women between 40 – 49 years of age should go for regular mammogram screenings once a year. If you are 50 years old or above, you should go for mammogram screenings once every 2 years.

A 3D mammogram can also be used to diagnose certain breast abnormalities, such as a suspicious lump or thickening of the skin. The procedure is especially useful for women with overlapping or dense breast tissue, which can be hard to examine using standard mammography.

Compared to a traditional mammogram, a 3D mammogram offers benefits such as:

Better detection of small masses hidden in dense breast tissue
Higher accuracy of breast cancer detection
Lower rate of false-positive cases
Reduces the need for follow-up imaging

What are the risks of a 3D mammogram?

Sometimes a mammogram may identify an abnormality which appears like cancer, but turns out to be normal. This is called a false positive. Likewise, there is also a small probability that mammograms may not detect cancer hidden by normal breast tissues. This is called a false negative.

How do you prepare for a 3D mammogram?

The best time to schedule a mammogram is 1 week following your period. Do not schedule your mammogram in the week before your period because breasts are usually tender during this time.

Always inform your doctor or radiographer if there is a possibility you are pregnant.
Wear a comfortable 2-piece outfit.
Do not use deodorant, perfume, powder or ointment on the underarms or breasts.
Bring along all your previous mammogram images and reports so they can be compared with your current images.
For an accurate diagnosis, you will be asked to fill in a questionnaire before the start of your mammogram. Ask the radiographer if you are unsure of how to answer any questions.

What can you expect during a 3D mammogram?

A 3D mammogram examination usually takes around 30 minutes.

During the procedure

The mammogram is performed by a specially trained female radiographer.

In the examination room, you will be asked to stand in front of the mammogram machine.
The radiographer will carefully position your breast on the detector plate and show you where you can comfortably place your arm.
Once properly positioned, your breast will be compressed to spread out the breast tissues. You may feel some discomfort on your breast. Do let the radiographer know if you experience any significant pain or discomfort.
The X-ray tube will move along the arc to take multiple images in a few seconds. You need to remain still so the images will not be blurry.
The same process will be repeated for your other breast.

When the examination is completed, you will be asked to wait for the radiographer to examine the images and determine if additional images are needed.