Mammograms are x-rays of the breast. They are used for both screening and diagnosis.
A screening mammogram is used to find breast changes in women who have no signs of breast cancer. Most women get two x-rays of each breast.
If your screening mammogram shows a breast change since your last one, or if you or your health care provider notice a change, you may need to have a diagnostic mammogram. That means more x-rays are taken to get clearer, more detailed pictures of the breast.
A digital mammogram is another way to take a picture of your breasts. The procedure for having a digital mammogram is the same as for a screening mammogram, except that it records the x-ray images in computer code instead of on x-ray film.
What Mammograms Can Show
The radiologist will look at your x-rays for breast changes that do not look normal. The doctor will look for differences in each breast. He or she will compare your past mammograms with your most recent one to check for changes. The doctor will also look for lumps and calcifications (see Possible Mammogram Results and Follow-Up Care).
Lump (or "mass")
The size, shape, and edges of a lump sometimes can give doctors information about whether or not it may be cancer. On a mammogram, a growth that is benign often looks smooth and round with a clear, defined edge. Breast cancer often has a jagged outline and an irregular shape.
A calcification is a deposit of the mineral calcium in the breast tissue. Calcifications appear as small white spots on a mammogram. There are two types:
- Macrocalcifications are large calcium deposits often caused by aging. These are usually not a sign of cancer.
- Microcalcifications are tiny specks of calcium that may be found in an area of rapidly dividing cells.
If calcifications are grouped together in a certain way, it may be a sign of cancer.
Depending on how many calcium specks you have, how big they are, and what they look like, your doctor may suggest that you have:
- A different type of mammogram that allows the radiologist to have a closer look at the area
- Another screening mammogram, usually within 6 months
- Other tests such as ultrasound or biopsy
Are Mammogram Results Always Right?
No. Although they are not perfect, mammograms are the best method to find breast changes. If your mammogram shows a breast change, sometimes other tests are needed to better understand it. Even if the doctor sees something on the mammogram, it does not mean it is cancer.