- What is a mammogram?
- What’s the difference between a screening mammogram and a diagnostic mammogram?
- How is a mammogram done?
- What to expect when you have a screening mammogram
- Where can I get help with mammogram costs?
- How is mammography regulated?
- Radiation exposure from mammography
- What does the doctor look for on a mammogram?
- Getting called back after a mammogram
- Understanding your mammogram report – BI-RADS categories
- What are the limitations of mammograms?
- Mammograms after breast cancer
- Mammograms in special circumstances
- Breast MRI (magnetic resonance imaging)
- Breast ultrasound
- Other breast imaging methods
- To learn more
Other breast imaging methods
A ductogram, also called a galactogram, is sometimes used to help find the cause of any worrisome nipple discharge. In this test, a very thin metal tube is put into the opening of a duct in the nipple that the discharge is coming from. A small amount of contrast material is put in. It outlines the shape of the duct on x-ray and can show whether there is a mass inside the duct.
Nuclear medicine studies
For nuclear medicine studies (also called nuclear scans) small amounts of radioactive substances are injected into the body and special cameras are used to see where they go. Depending on the substance used, different types of abnormalities may be found. Unlike most other imaging tests that are based on changes tumors cause in the body’s structure, nuclear medicine scans depend on changes in tissue metabolism. A couple of newer subtypes of nuclear medicine studies are described below under “Other experimental breast imaging tests.”
PET (positron emission tomography) scan
For a PET scan, glucose (a form of sugar) that contains a radioactive atom is injected into the bloodstream. Because cancer cells grow rapidly, they absorb large amounts of the radioactive sugar. After about an hour, a special camera is used to create a picture of areas of radioactivity in the body. Some machines are able to do both a PET and CT scan at the same time (PET/CT scan). This lets the radiologist compare areas of higher radioactivity on the PET with the detailed picture of that area on the CT.
PET scans have been studied to see if they can help distinguish between malignant or benign tumors in the breast, but they aren’t accurate enough to be helpful. More often, PET/CT scans are used in patients known to have breast cancer to see if the cancer has spread.
Scintimammography (molecular breast imaging)
A radioactive tracer known as technetium sestamibi has been studied to help detect breast cancer. For this test, a small amount of the radioactive tracer is put into a vein. The tracer attaches to breast cancer cells and is detected by a special camera.
This test is not used as a screening test. Some radiologists believe this test may be helpful in looking at suspicious areas found by mammogram. But based on previous studies, scintimammography is not as good as MRI at finding cancers.
Current research is aimed at improving the technology and evaluating its use in specific situations, such as in women with dense breasts.
Electrical impedance imaging (T-scan™)
Electrical impedance imaging (EIT) scans the breast for electrical conductivity. It’s based on the idea that breast cancer cells conduct electricity in a different way than normal cells. The test passes a very small electrical current through the breast and then detects it on the skin of the breast. This is done using small electrodes that are taped to the skin. EIT does not use radiation or compress the breasts.
This test is FDA approved as a diagnostic aid in helping classify tumors found on mammogram. But at this time it has not had enough clinical testing to be used in breast cancer screening.
Thermography (thermal imaging)
Thermography is a way to measure and map the heat on the surface of the breast using a special heat-sensing camera. It’s based on the idea that the temperature rises in areas with increased blood flow and metabolism, which could be a sign of a tumor.
Thermography has been around for many years, but studies have shown that it’s not an effective screening tool for finding breast cancer early. Although it has been promoted as helping detect breast cancer early, a 2012 research review found that thermography was able to detect only a quarter of the breast cancers found by mammography. In other words, it failed to detect 3 out of 4 cancers that were known to be present in the breast. Digital infrared thermal imaging (DITI), which some people believe is a newer and better type of thermography, has the same failure rate. This is why thermography should not be used as a substitute for mammograms.
Other experimental breast imaging tests
Some newer techniques are now being studied for breast imaging. These tests are in the earliest stages of research. It will take time to see if any of these imaging tests are as good as or better than those we use today.
Optical imaging tests pass light into the breast and then measure the light that returns or passes through the tissue. The technique does not use radiation and does not require breast compression. Studies going on now are looking at combining optical imaging with other tests like MRI or 3D mammography to help diagnose breast cancer.
Molecular breast imaging (MBI) is a newer nuclear medicine imaging technique for the breast. It’s being studied as a way to follow up breast problems (such as a lump or an abnormal mammogram). It is also being studied in addition to mammograms for women with dense breasts.
Positron Emission Mammography (PEM) is another newly developed imaging exam of the breast. It uses sugar attached to a radioactive particle to detect cancer cells. The PEM scanner is FDA approved. Working much like a PET scan, a PEM scan may be better able to detect small clusters of cancer cells within the breast. Right now it is being studied in women with breast cancer or other breast problems to see if it can predict which lumps are cancers.
Last Medical Review: 12/08/2014
Last Revised: 12/08/2014