A mammogram is an X-ray image of your breast that’s used to detect cancer. It’s an important test because it can detect breast cancer in its very early stages before you have any signs, such as a breast lump. This is important because the earlier breast cancer is detected, the more treatable it is.

According to the American Cancer Society, women with an average risk of breast cancer should start getting yearly mammograms at age 45. If you’re over the age of 40 but younger than 45, you can begin getting mammograms every year if you want.

At the age of 55, it’s recommended that all women have a mammogram every other year. But, if you prefer, you can choose to have a mammogram every year.

Read on to learn more about the types of mammograms, how long a mammogram takes, and what to expect during the procedure and afterward.

There are two types of mammograms. Let’s take a closer look at each one.

Screening mammogram

A screening mammogram is done when you have no problems or concerns about your breasts. It’s the type of mammogram that’s done during your annual or biannual screening. It can detect the presence of breast cancer in the absence of any signs or symptoms.

This is the type of mammogram that’s described in more detail in this article.

Diagnostic mammogram

A diagnostic mammogram looks at a specific area of your breast. It’s done for several reasons:

  • to evaluate an area of your breast that has a lump or other signs that might indicate cancer
  • to further evaluate a suspicious area seen on a screening mammogram
  • to reevaluate an area that’s been treated for cancer
  • when something such as breast implants obscure the images on a regular screening mammogram

From checking in to leaving the facility, the entire process of getting a mammogram typically takes about 30 minutes.

The time can vary for several reasons, including:

  • how long you’re in the waiting room
  • how long it takes you to fill out the pre-exam questionnaire
  • how long it takes you to undress before the procedure and dress again afterward
  • the time it takes the technician to position your breasts correctly
  • if an image has to be retaken because it doesn’t include the entire breast or the image wasn’t clear enough

The mammogram itself usually only takes about 10 minutes.

Because your breast tissue has to be compressed to obtain a good image, which can cause some discomfort, you may want to consider the time of the month that you schedule a mammogram.

Your breasts are usually most tender during and right before your period. So, you may want to schedule your mammogram 2 weeks before or 1 week after your menstrual period.

After checking in at the imaging facility, you may sit in the waiting room until you’re called for your mammogram. You may be asked to fill out a questionnaire while you wait.

Next, a technician will call you back to a room with a mammogram machine. If you haven’t already filled out a questionnaire, the technician will ask you to do so. This form has questions about:

The technician will also confirm that you’re not pregnant.

You’ll be asked to undress from the waist up after the technician leaves the room. You’ll put on a cotton gown. The opening should be in the front.

You’ll also need to remove necklaces and other jewelry. Deodorant and talcum powder can interfere with the images, so you’ll be asked to wipe these off if you’re wearing any.

What happens during a mammogram?

  1. Once you’re in the gown, you’ll be asked to stand next to the mammogram machine. You’ll then remove one arm from the gown.
  2. The technician will position your breast on a flat plate and then lower another plate to compresses and spread out your breast tissue. This may be uncomfortable, but it’ll only last a few seconds.
  3. Once your breast is positioned between the plates, you’ll be asked to hold your breath. While you’re holding your breath, the technician will quickly take the X-ray. The plate will then lift off your breast.
  4. The technical will reposition you so that a second image of the breast can be obtained from a different angle. This sequence is then repeated for your other breast.
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The technician will leave the room to check the X-rays. If an image doesn’t adequately show the entire breast, it’ll need to be retaken. When all the images are acceptable, you can get dressed and leave the facility.

A traditional 2-dimensional (2-D) mammogram produces two images of each breast. One image is from the side and another is from the top.

If your breast tissue isn’t spread out completely or compressed enough, it can overlap. The image of overlapping tissue can be difficult for the radiologist to evaluate, making abnormalities easier to miss. The same problem can occur if your breast tissue is dense.

A 3-dimensional (3-D) mammogram (tomosynthesis) takes multiple images of each breast, creating a 3-D image. The radiologist can scroll through the images, which makes it easier to see abnormalities even when breast tissue is dense.

Multiple images eliminate the problem of tissue overlap but increase the time it takes to have a mammogram done.

A recent study suggested that 3-D mammograms were better than 2-D mammograms for women 65 and older. The 3-D mammograms found fewer areas that resembled cancer but were actually normal than 2-D mammograms.

3-D mammograms may also find more cancers than 2-D mammograms.

Although the American Society of Breast Surgeons prefers 3-D mammograms for all women over 40, 2-D mammograms are still used more often because many insurance companies don’t cover the extra cost of 3-D.

Almost all mammograms are done digitally, so the images are stored electronically instead of on film. This means the images can be viewed by the radiologist on a computer as they’re being taken.

However, it usually takes a day or two for the radiologist to look at the images and then another couple of days for the radiologist’s dictation to be typed. This means your primary care doctor often has the results back 3 to 4 days after your mammogram.

Most doctors or healthcare providers will contact you right away if an abnormality is found so that you can schedule a diagnostic mammogram or other tests to evaluate it.

When your mammogram is normal, your doctor might contact you right away. In most cases, your doctor will mail you the results, which means it could take a few days to receive the results.

All in all, you should have your results within a week or two of having a mammogram, but this may vary.

Talking to your doctor or healthcare provider will give you the best idea of how and when to expect your results.

It’s important to remember that an abnormal mammogram doesn’t mean you have cancer. According to the American Cancer Society, fewer than 1 in 10 women with an abnormal mammogram have cancer.

Still, an abnormal mammogram should be investigated to make sure it’s not cancer.

If an abnormality is seen on your mammogram, you’ll be asked to return for additional testing. This is often done as soon as possible so that treatment can begin right away if needed.

A follow-up will typically involve a diagnostic mammogram that takes detailed images of the abnormal area. Other tests may include:

  • evaluating the abnormal area with an ultrasound
  • reevaluating the abnormal area with an MRI scan because the X-ray was inconclusive or further imaging is needed
  • surgically removing a small piece of tissue to look at under a microscope (surgical biopsy)
  • removing a small piece of tissue through a needle to examine under a microscope (core-needle biopsy)

A mammogram is an important screening test for breast cancer. It’s a simple imaging study that usually takes about 30 minutes. You typically have the results within a week or two.

Most of the time, an abnormality seen on a mammogram isn’t cancer. When cancer is found with a mammogram, it’s often at a very early stage, when it’s most treatable.