A mammogram is a black-and-white image of your breast used to screen for breast cancer. Mammograms play a key role in early breast cancer detection and help decrease breast cancer deaths.
During a mammogram, you stand in front of an X-ray machine designed for mammography. A technician places your breast on a platform that holds the X-ray film and positions the platform to match your height. The technician helps you position your head, arms and torso to allow an unobstructed view of your breast.
During a mammogram, your breasts are compressed between two firm surfaces in order to spread out the breast tissue. Then, an X-ray captures images of your breasts that a doctor uses to detect changes and cancer.
A mammogram can be used either for screening or for diagnostic purposes. How often you should have a mammogram depends on your age and your risk of breast cancer.
Why it's done
Mammography is X-ray imaging of your breasts designed to detect tumors and other abnormalities. Mammography can be used either for screening or for diagnostic purposes in evaluating a breast lump:
- Screening mammography. Screening mammography is used to detect breast changes in women who have no signs or symptoms or observable breast abnormalities. The goal is to detect cancer before any clinical signs are noticeable. This usually requires at least two mammograms from different angles of each breast.
- Diagnostic mammography. Diagnostic mammography is used to investigate suspicious breast changes, such as a breast lump, breast pain, an unusual skin appearance, nipple thickening or nipple discharge. It's also used to evaluate abnormal findings on a screening mammogram. Additional images can be made from other angles or focus on areas of concern at higher magnification.
When to begin screening mammography
Experts don't agree on when women should begin regular mammograms or how often the tests should be performed. Your doctor can recommend a screening mammography schedule for you.
Breast density — The four grades
Breast tissue is composed of fatty (nondense) tissue and connective (dense) tissue. Radiologists use a grading system to describe the density of breast tissue based on the proportion of fat to connective tissue. The four grades of density are shown in these mammogram images. From left to right: grade 1 (a very fatty breast), grade 2 (fatty tissue makes up more than 50 percent of breast), grade 3 (dense tissue makes up more than 50 percent of the breast) and grade 4 (a very dense breast with very little fat).
Some general guidelines for when to begin screening mammography include:
- If you have an average risk of breast cancer, discuss when to begin mammograms with your doctor. Many women begin mammograms at age 40 and have them every one to two years. Professional groups differ on their recommendations, with most, including the American Cancer Society, advising women with an average risk to begin mammograms at age 40 and the U.S. Preventive Services Task Force recommending women wait until age 50 to begin regular mammograms.
- If you have a high risk of breast cancer, you may benefit by beginning screening mammograms before age 40. Talk to your doctor for an individualized program. Your risk factors and your degree of breast density may lead your doctor to recommend magnetic resonance imaging (MRI) in combination with mammograms.
Mammography isn't foolproof. It does have some limitations and potential risks:
- Mammography exposes you to low-dose radiation. The dose is very low, though, and for most women the benefits of regular mammography outweigh the risks posed by this amount of radiation.
- Mammograms aren't always accurate. The accuracy of the procedure depends in part on the quality of the film, the technique used, and the experience and skill of the radiologist. Other factors — such as your age and breast density — may result in false-negative or false-positive mammograms. Always tell your doctor if you've noticed a change in one of your breasts, especially if your mammogram is interpreted as normal.
- Mammograms in younger women can be difficult to interpret. The breasts of younger women contain more glands and ligaments than do those of older women, resulting in dense breast tissue that can obscure signs of cancer. With age, breast tissue becomes fattier and has fewer glands, making it easier to detect changes on mammograms.
- Having a mammogram may lead to additional testing. Among women of all ages, about 10 percent of mammograms require additional testing. However, most abnormal findings aren't cancer. If you're told that your mammogram is abnormal, make sure that the radiologist has compared your current mammogram with any previous mammograms.
- Screening mammography can't detect all cancers. Some cancers detected by physical examination may not be seen on the mammogram. A cancer may be too small or may be in an area that is difficult to view by mammography, such as your armpit. Mammograms can miss 1 in 5 cancers in women.
- Not all of the tumors found by mammography can be cured. Certain types of cancers are aggressive, grow rapidly and spread early to other parts of your body.
If your mammogram shows areas of concern that may be cancer, the radiologist may recommend additional mammograms or an ultrasound. A breast biopsy may be recommended if the area continues to appear suspicious. A biopsy is a procedure to remove a piece of tissue or a sample of cells from your body so that it can be analyzed by a pathologist — a doctor who specializes in examining body tissues. If your mammogram or biopsy shows that you have breast cancer, you and your doctor can discuss the best course of treatment.
If the breast biopsy results are normal or reveal a benign breast condition, talk with your doctor to be sure that the radiologist and the pathologist drew the same conclusions from your mammogram and your biopsy. If they have interpreted your test results differently, you may need further testing.
How you prepare
Schedule the test for a time when your breasts are least likely to be tender. If you haven't gone through menopause, that's usually during the week after your menstrual period. Your breasts are most likely to be tender the week before and the week during your period.
Ask whether the mammogram facility is certified by the Food and Drug Administration. This certification will ensure that the facility meets certain standards.
If you're going to a new facility for your mammogram, gather any prior mammograms and bring them with you to your appointment so that the radiologist can compare them with your new images. It's important to bring the original mammogram films, not copies, and accompanying reports.
Avoid using deodorants, antiperspirants, powders, lotions, creams or perfumes under your arms or on your breasts. Metallic particles in powders and deodorants could be visible on your mammogram and cause confusion.
Taking an over-the-counter pain medication, such as aspirin, acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin, others), about an hour before your mammogram might ease the discomfort of the test.
What you can expect
- During the test
At the testing facility, you're given a gown and asked to remove neck jewelry and clothing from the waist up. It's a good idea to wear a two-piece outfit that day.
For the procedure itself, you stand in front of an X-ray machine specially designed for mammography. The technician places one of your breasts on a platform that holds the X-ray film and raises or lowers the platform to match your height. The technician helps you position your head, arms and torso to allow an unobstructed view of your breast.
Your breast is gradually pressed against the platform by a clear plastic plate. Pressure is applied for a few seconds to spread out the breast tissue. The pressure isn't harmful, but you may find it uncomfortable or even painful. If you have too much discomfort, inform the technician.
Your breast must be compressed to even out its thickness and permit the X-rays to penetrate the breast tissue. The pressure also holds your breast still to decrease blurring from movement and minimizes the dose of radiation needed. During the brief X-ray exposure, you'll be asked to stand still and hold your breath.
- After the test
After images are made of both your breasts, you may be asked to wait while the technician checks the quality of the images. If the views are inadequate for technical reasons, you may have to repeat part of the test. The entire procedure usually takes less than 30 minutes. Afterward, you may dress and resume normal activity.
It's required that the mammogram facility send your results within 30 days, but you can usually expect to receive your results within five business days.
Mammography produces mammograms — black-and-white images of your breast tissue on X-ray film. If your mammogram is digital, images are electronic and are displayed on a video monitor or are printed off for viewing. A radiologist interprets the images and sends a written report of the findings to your doctor.
The radiologist looks for evidence of cancer or noncancerous (benign) conditions that may require further testing, follow-up or treatment.
Possible findings include:
- Calcium deposits (calcifications) in ducts and other tissues
- Masses or lumps
- Distorted tissues
- Dense areas appearing in only one breast
- Dense areas that have appeared since your last mammogram
Calcifications can be the result of cell secretions, cell debris, inflammation, trauma, previous radiation or foreign bodies. Tiny, irregular deposits called microcalcifications may be associated with cancer. Larger, coarser deposits called macrocalcifications may be caused by aging or injury or by a benign condition such as fibroadenoma, a common noncancerous tumor of the female breast. Most breast calcifications are benign, but if calcifications appear worrisome, the radiologist might order additional diagnostic images with magnification.
Breast calcifications on mammogram
Calcifications are small calcium deposits in the breast that show up as white spots on a mammogram. Large, round, well-defined calcifications (left column) are more likely to be noncancerous (benign). Tight clusters of tiny, irregularly shaped calcifications (right column) may indicate cancer.
Dense areas indicate tissue with many glands and can make calcifications and masses more difficult to identify. They could also represent cancer. Distorted areas suggest tumors that may have invaded neighboring tissues.
If the radiologist notes areas of concern on your mammogram, further testing may include additional mammograms known as compression or magnification views, as well as ultrasound imaging or a biopsy. Some situations require the use of diagnostic magnetic resonance imaging (MRI) in areas where the current imaging with mammography or ultrasound is negative.
A mammogram is a picture of your breast taken with a safe, low-dose X-ray machine. It's the most effective exam for early detection of breast cancer.
There are two types of mammography exams: screening and diagnostic. A routine screening mammogram is performed when you have no symptoms. Ask your doctor when you should begin regular screening mammograms.
A diagnostic mammogram is performed if there is concern regarding your breasts or if a screening mammogram requires additional studies. You don't need to prepare for a mammogram. You can eat normally, and if you take medications, continue to do so. However, you may be asked not to wear deodorant on the day of your mammogram because such products may show up on mammogram images. Also, if you are premenopausal, it's best to schedule your screening exam during the week following your menstrual period, when your breasts may be less tender.
Once checked in, you'll undress from the waist up and wear a special robe. A mammography technologist will perform your mammogram. She has specialized training in mammographic positioning and techniques.
If you are asked to complete a breast-health survey prior to your exam, your technologist can assist and review the survey with you.
Once in the exam room, you'll be asked to stand in front of the mammography unit, a special type of X-ray machine. It can move up and down and side to side.
Your technologist will position your breast between two firm surfaces that compress your breast as flat as possible, to ensure good X-ray pictures. For example, here you can see how the machine flattens the technologist's hand.
She may also switch paddles to get a different view.
Compression is necessary to spread the breast tissue and eliminate motion, which may blur the picture. This may be uncomfortable but shouldn't hurt.
Compression usually lasts no more than 20 to 30 seconds. During this time, an X-ray beam comes from above and penetrates your breast tissue. The X-ray image is either created on a film cassette, located below your breast, or recorded digitally and stored in a computer. Denser tissue, such as cancer, appears bright and white, whereas less dense tissue, such as fat, appears dark or gray.
The images are then processed and made available for review and interpretation.
Here we see a baseline mammogram of a 40-year-old woman. Five years later, her formerly clear image now shows cancer.
Don't be concerned if you are asked to remove your gown or reposition, even if it means standing on your toes. This ensures that your gown won't interfere with the pictures and that you are standing correctly. If you are uncomfortable, please tell your technologist.
After the pictures are taken, you may be asked to wait while the X-ray images are processed.
During this time, technologists check your images to assure they are acceptable. If they aren't clear, you may be asked to have more X-rays done. Don't be alarmed if this happens, your technologist simply wants the best images.
A doctor trained to read X-ray images, a radiologist, will examine your mammograms. Under federal regulations, the radiologist must be experienced in reading mammograms.
If no further studies are required, you'll be released and can resume your regular activities.
Based on what your radiologist sees on your mammogram, you may be asked to return for a diagnostic mammogram. It's not unusual to be called back after a screening mammogram. This is because your radiologist may not have any previous comparison or may need to look more carefully at a specific area of the breast. The additional imaging is usually necessary to clarify a finding on your screening mammogram. Most findings are not cancer, but it's important to have the additional imaging done. This may include specialized and tightly focused X-ray pictures, known as a magnification or compression view, or possibly a breast ultrasound.