A mammogram is a type of X-ray of the breasts. A screening mammogram usually involves two X-rays of each breast. A diagnostic mammogram involves more X-rays.
Who is a candidate for the test?
A screening mammogram is generally used to detect breast cancer or other changes in the breast tissue in women who do not have symptoms.
A diagnostic mammogram may be ordered when a screening mammogram shows something abnormal in the breast.
It may also be ordered if the woman has symptoms, such as:
- a discharge from the nipple other than breast milk
- a lump or swelling in the breast or underarm area
- nipple pain
- redness or scaliness of the nipple or breast skin
- retraction, or turning inward, of the nipple
- skin irritation or dimpling
Breast cancer screening with mammograms has reduced deaths from breast cancer in women 40 to 69 years of age.
How is the test performed?
For a screening mammography, the woman undresses to the waist and puts on a gown that opens from the front. The technologist places one breast on an X-ray film cassette, which resembles a metal shelf. The woman rests her breast on the film cassette. Usually the woman stands during this procedure.
A plastic paddle briefly squeezes the breast from above to flatten it out. This allows a clearer X-ray to be taken. Two views are usually taken of each breast for a screening mammogram. A diagnostic mammogram requires more views and more detail than the screening exam.
With modern mammography equipment used specifically for breast X-rays, very low levels of radiation are used. Some mammography units offer a stereotactic (x-ray guided) biopsy of any suspicious areas at the time of the examination. A woman is counseled and prepared for this by her healthcare professionals.
Examples of these newer techniques employed to gain a better diagnosis of breast abnormalities include:
digital mammography, which records images in computer code instead of on X-ray film
MRI imaging, which uses a large magnet and radio frequencies to produce pictures of the breast tissue
positron emission tomography, or PET, which uses radioactive materials to create computer images
radionuclides, which uses contrast agents
- ultrasound, which uses high-frequency sound waves instead of X-rays
What is involved in preparation for the test?
It is recommended that a mammogram be scheduled one week after a woman's last period. Women should not wear powder, deodorant, lotion, or perfume under the arms or on the breasts. Wearing a two-piece outfit is suggested. Prior to the exam, all jewelry and metal objects need to be removed.
What do the test results mean?
A mammogram can detect breast cancer
, often before a lump can be felt. A mammogram may also show the following conditions:
- calcifications, or mineral deposits
- cysts, or fluid-filled masses
- leaking breast implants
- noncancerous tumors or growths