A mammography exam, called a mammogram, is used to aid in the early detection and diagnosis of breast diseases in women. Mammography is a specific type of imaging that uses a low-dose x-ray system to examine the women breast and is used as a diagnostic as well as a screening tool. Screening mammograms usually involve two x-rays of each breast. The goal of mammography is the early detection of breast cancer, typically through detection of characteristic masses and/or microcalcifications. They are recommended for women who have symptoms of breast cancer or who have a high risk of the disease. Mammograms can show tumors long before they are big enough for you or your health care provider to feel.
X-rays are the oldest and most frequently used form of medical imaging. Mammograms are quick and easy. A mammogram takes only a few seconds and it can help save your life. Like all x-rays, mammograms use doses of ionizing radiation to create images. Radiologists then analyze the image for any abnormal findings.
THERE are two methods mammogram digital and conventional mammography . Both digital and conventional mammography use x-rays to produce an image of the breast; however, conventional mammography stores the image directly on film, whereas digital mammography takes an electronic image of the breast and stores it directly in a computer. Because digital mammography allows a radiologist to electronically adjust, store, and retrieve digital images, digital mammography may offer the following advantages over conventional mammography:
- Health care providers can share image files making long-distance consultations with other mammography specialists .
- Subtle differences between normal and abnormal tissues may be more easily noted.
- The number of follow-up procedures needed may be fewer.
- Fewer repeat images may be needed, reducing the exposure to radiation.
And two different types of mammograms:
Screening mammograms are done for women who have no symptoms of breast cancer. It usually involves two x-rays of each breast. Screening mammograms can detect lumps or tumors that cannot be felt. They can also find microcalcifications (my-kro-kal-si-fi-KAY-shuns) or tiny deposits of calcium in the breast, which sometimes mean that breast cancer is present.
Diagnostic mammograms are used to evaluate a patient with abnormal clinical findings—such as a breast lump or lumps or other symptom or sign of breast cancer has been found. Signs of breast cancer may include pain, thickened skin on the breast, nipple discharge, or a change in breast size or shape. Diagnostic mammography may also be done after an abnormal screening mammography in order to evaluate the area of concern on the screening exam. A diagnostic mammogram takes longer than a screening mammogram because it involves more x-rays in order to obtain views of the breast from several angles. The technician can magnify a problem area to make a more detailed picture, which helps the doctor make a correct diagnosis.
Before scheduling a mammogram discuss any new findings or problems in your breasts with your doctor. In addition, inform your doctor of any prior surgeries, hormone use, and family or personal history of breast cancer.
- Do not schedule your mammogram for the week before your menstrual period if your breasts are usually tender during this time. The best time for a mammogram is one week following your menstrual period. Always inform your doctor or x-ray technologist if there is any possibility that you are pregnant.
- If you have breast implants, be sure to tell your mammography facility that you have them when you make your appointment.
- Do not wear deodorant, talcum powder or lotion under your arms or on your breasts on the day of the exam. These can appear on the mammogram as calcium spots.
A mammography unit is a rectangular box that houses the tube in which x-rays are produced. The unit is used exclusively for x-ray exams of the breast, with special accessories that allow only the breast to be exposed to the x-rays. Attached to the unit is a device that holds and compresses the breast and positions it so images can be obtained at different angles.
During mammography, a specially qualified radiologic technologist will position your breast in the mammography unit. Your breast will be placed on a special platform and compressed with a paddle (often made of clear Plexiglas or other plastic). The technologist will gradually compress your breast.
Breast compression is necessary in order to:
- Even out the breast thickness so that all of the tissue can be visualized.
- Spread out the tissue so that small abnormalities are less likely to be obscured by overlying breast tissue.
- Allow the use of a lower x-ray dose since a thinner amount of breast tissue is being imaged.
- Hold the breast still in order to minimize blurring of the image caused by motion.
- Reduce x-ray scatter to increase sharpness of picture.
You will be asked to change positions between images. The routine views are a top-to-bottom view and an oblique side view. The process will be repeated for the other breast.
You must hold very still and may be asked to keep from breathing for a few seconds while the x-ray picture is taken to reduce the possibility of a blurred image. The technologist will walk behind a wall or into the next room to activate the x-ray machine.
When the examination is complete, you will be asked to wait until the radiologist determines that all the necessary images have been obtained.
The radiologist will look at your x-rays for breast changes that do not look normal and 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.
- 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.
- Calcification. 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 usually are 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 other tests. Calcium in the diet does not create calcium deposits, or calcifications, in the breast.
If you have a screening test result that suggests cancer, your doctor must find out whether it is due to cancer or to some other cause. Initial mammographic images themselves are not usually enough to determine the existence of a benign or malignant disease with certainty. If a finding or spot seems suspicious, your radiologist may recommend further diagnostic studies.
- Diagnostic mammogram, to focus on a specific area of the breast
- Ultrasound, or imaging test that uses a device with sound waves to create a picture of your breast. The pictures may show whether a lump is solid or filled with fluid. A cyst is a fluid-filled sac. Cysts are not cancer. But a solid mass may be cancer.
- Magnetic resonance imaging (MRI), which uses a powerful magnet linked to a computer. MRI makes detailed pictures of breast tissue.
- Biopsy, a test in which fluid or tissue is removed from your breast to help find out if there is cancer. The biopsy procedure will be used to obtain actual tissue from the site for the pathologist to examine microscopically to determine the precise cause of the abnormality.
Not all cancers of the breast can be seen on mammography. While mammography is the best screening tool for breast cancer available today, mammograms do not detect all breast cancers. Also, a small portion of mammograms indicate that a cancer could possibly be present when it is not (called a false-positive result).