Mammography uses radiation to produce detailed images of the breasts. It’s used in routine screening and to aid in the diagnosis of breast cancer.
In the United States, mammograms are a common early detection tool. In 2013, 66.8 percent of women 40 years old and over had had a mammogram within the previous two years.
Mammography is a common way to screen for breast cancer, but it’s not the only screening tool.
Read on to learn more about different types of mammography, as well as the potential benefits and risks of alternative or complementary screening tools.
Film and digital mammograms are both considered to be the “standard” form of mammography. They’re performed in the same way.
You’ll disrobe from the waist up and put on a gown that opens in front. As you stand in front of the machine, a technician will position your arms and place one breast on a flat panel. Another panel from above will compress your breast.
You’ll be asked to hold your breath for a few seconds while the machine takes a picture. This will be repeated several times for each breast.
The images are viewed and stored on sheets of film or as digital files that can be viewed on a computer. In the United States, you’re more likely to have digital mammography.
Digital has a few advantages over film. Digital files can be easily shared among doctors. The images can also be enlarged for better viewing, and suspicious areas can be enhanced.
Mammograms are a good early detection tool. They’ve been shown to reduce deaths from breast cancer in women ages 40 to 74. They can sometimes be uncomfortable, but generally don’t cause severe pain or side effects.
There are some concerns, though. Screening mammograms miss 1 in 5 breast cancers. This is called a false negative.
Not all suspicious breast tissue turns out to be cancer. Abnormal mammograms call for additional testing to rule out breast cancer. This is called a false positive.
Mammography uses low doses of radiation. The risk of harm from a mammogram is low, but it does have the potential to cause cancer when repeated over time. Also, radiation should be avoided if you’re pregnant.
Under the Affordable Care Act (ACA), breast cancer mammography screenings are covered for women over 40 every one or two years. It’s usually covered under Medicare as well.
3-D mammography is a newer type of digital mammography, but it’s performed in much the same way as other mammograms.
Images are taken in thin slices and at multiple angles, then combined to make a complete picture. It may be easier for radiologists to see breast tissue more clearly in 3-D.
3-D mammography requires about the same amount of radiation as digital mammography. However, more pictures are needed, which may lengthen the testing time and the amount of radiation exposure.
It’s not yet clear if 3-D is better than standard digital at detecting early breast cancer or lowering the false-positive or false-negative rates.
Ultrasound uses high-frequency sound waves rather than radiation to produce pictures of the breast.
For the procedure, some gel will be placed on your skin. Then a small transducer will be guided over your breast. The pictures will appear on a screen.
This is a painless procedure that typically doesn’t cause side effects.
Ultrasound of the breast may be used after an abnormal mammogram or in women with dense breast tissue. It’s not usually used in routine breast cancer screening for women at average risk.
A 2015 study found that ultrasound and mammography detected breast cancer at about the same rate. Breast cancers found by ultrasound were more likely to be of the invasive kind and lymph node-negative.
Ultrasound also resulted in more false positives than mammography.
The study authors wrote that where mammography is available, ultrasound should be considered a supplemental test. In countries where mammography isn’t available, it should be used as an alternative.
MRI doesn't rely on radiation. It uses magnets to create cross-sectional images of your breast. It’s painless and normally doesn’t involve side effects.
If you have a breast cancer diagnosis, MRI can help find additional tumors and assess tumor size.
MRI is usually not recommended as a screening tool for women at average risk of breast cancer. It’s not as effective as mammography in finding tumors and is more likely to produce a false-positive result.
Insurance may not cover MRI as a breast screening tool.
Molecular breast imaging (MBI) is a newer test and may not be available near you yet.
MBI involves a radioactive tracer and a nuclear medicine scanner. The tracer is injected into a vein in your arm. If you have cancer cells in your breast, the tracer will light up. The scanner is used to detect those areas.
This test is sometimes used in addition to a mammogram to screen women with dense breast tissue. It’s also used to evaluate abnormalities found on a mammogram.
The test does expose you to a low dose of radiation. There’s a rare chance of allergic reaction to the radioactive tracer as well. MBI may produce a false-positive result or miss small cancers or cancer located close to the chest wall.
MBI may not be covered as a routine breast screening test.
Although general screening guidelines exist, there are many things that can factor into how you should be screened for breast cancer. This is a discussion you should have with your doctor.
Here are some things to consider when choosing breast cancer screening methods:
- doctor recommendation
- experiences and results of previous tests
- benefits and risks of each type you’re considering
- existing medical conditions, pregnancy, and overall health
- family and personal history of breast cancer
- what tests are covered under your health insurance policy
- what tests are available in your area
- personal preferences
Women with dense breasts are advised to have annual film or digital mammograms.
It may be harder to detect cancer in dense breast tissue, particularly if there are no earlier mammograms for comparison.
You may not need additional testing, though. Ask your doctor if ultrasound or MRI is a good idea. This may be particularly important if you’re at higher than average risk of developing breast cancer.
If you have implants, you still need regular breast cancer screening. Film or digital mammograms are recommended.
Make sure the mammogram technician knows you have implants prior to the procedure. They might need to take extra images because implants can hide some breast tissue.
The radiologist who reads the images will need to know, too.
It’s rare, but a breast implant can rupture during a mammogram. Ask your doctor if ultrasound or MRI are advisable.
There’s no one-size-fits all rule for breast cancer screening. Much depends on your individual risk factors and comfort level with each screening method.
According to current research, a woman’s risk for developing breast cancer during the next 10 years, starting at age 30, is as follows:
- At age 30, you have a 1 in 227 chance of developing breast cancer.
- At age 40, you have a 1 in 68 chance.
- At age 50, you have a 1 in 42 chance.
- At age 60, you have a 1 in 28 chance.
- At age 70, you have a 1 in 26 chance.
It’s important to note that your risk for breast cancer may be higher or lower depending on your individual risk factors. Your doctor will be your best resource in determining what your personal level of risk is and how to best go about screening.