• About |
• What To Expect |
• Common Uses for the Test |
• Risks and Benefits

About

Mammography is a special type of x-ray imaging used to create detailed images of the breast. It is estimated that 48 million mammograms are performed each year in the United States. Mammography uses low dose x-ray; high contrast, high-resolution film; and an x-ray system designed specifically for imaging the breasts. Successful treatment of breast cancer depends on early diagnosis. Mammography plays a major role in early detection of breast cancers. The US Food and Drug Administration reports that mammography can find 85 to 90 percent of breast cancers in women over 50 and can discover a lump up to two years before it can be felt. The benefits of mammography far outweigh the risks and inconvenience.

Mammography can show changes in the breast well before a woman or her physician can feel them. Once a lump is discovered, mammography can be key in evaluating the lump to determine if it is cancerous. If a breast abnormality is found or confirmed with mammography, additional breast imaging tests such as ultrasound (sonography) or a breast biopsy may be performed. A biopsy involves taking a sample(s) of breast tissue and examining it under a microscope to determine whether it contains cancer cells. Many times, mammography or ultrasound is used to help the radiologist or surgeon guide the needle to the correct area in the breast during biopsy.

There are two types of mammography exams, screening and diagnostic:
• Screening mammography is an x-ray examination of the breasts in a woman who is asymptomatic (has no complaints or symptoms of breast cancer). The goal of screening mammography is to detect cancer when it is still too small to be felt by a woman or her physician. Early detection of small breast cancers by screening mammography greatly improves a woman's chances for successful treatment. Screening mammography is recommended every one to two years for women once they reach 40 years of age and every year once they reach 50 years of age. In some instances, physicians may recommend beginning screening mammography before age 40 (i.e. if the woman has a strong family history of breast cancer). Screening mammography is available at a number of clinics and locations.

• Diagnostic mammography is an x-ray examination of the breast in a woman who either has a breast complaint (for example, a breast lump or nipple discharge is found during self-exam) or has had an abnormality found during screening mammography. Diagnostic mammography is more involved and time-consuming than screening mammography and is used to determine exact size and location of breast abnormalities and to image the surrounding tissue and lymph nodes. Typically, several additional views of the breast are imaged and interpreted during diagnostic mammography. Thus, diagnostic mammography is more expensive than screening mammography. Women with breast implants or a personal history of breast cancer will usually require the additional views used in diagnostic mammography.

Breast Compression During Mammography:
Breast compression is necessary to flatten the breast so that the maximum amount of tissue can be imaged and examined. For example, inadequate compression can lead to poor imaging of microcalcifications, tiny calcium deposits that are often an early sign of breast cancer. Breast compression may cause some discomfort, but it only lasts for a brief time during the mammography procedure. Patients should feel firm pressure due to compression but no significant pain. If you feel pain, please inform the technologist. During the mammography examination, breast compression should only be applied two to four times per breast for a few seconds each time.

Breast compression is necessary during mammography in order to:
• Flatten the breast so there is less tissue overlap for better visualization of anatomy and potential abnormalities.

• Reduce overlapping normal shadows, which can appear as suspicious regions on the film.

• Allow the use of a lower x-ray dose since a thinner amount of breast tissue is being imaged

• Immobilize the breast in order to eliminate image blurring caused by motion

• Reduce x-ray scatter which also leads to image degradation

What To Expect

You will be asked to complete a short medical history specific to your breast health. You will then be asked to disrobe from the waist up and be given a gown.

During mammography, the technologist will position the patient and image each breast separately. One at a time, each breast is carefully positioned on a special film cassette and then gently compressed with a paddle (often made of clear Plexiglas or other plastic). This compression flattens the breast so that the maximum amount of tissue can be imaged and examined. This occurs whether the exam is digital or film.

At some facilities, mammography technologists may place adhesive markers to the breast skin prior to taking images of the breast. The purpose of the adhesive markers is twofold: first, to identify areas with moles, blemishes or scars so that they are not mistaken for abnormalities, and secondly, to identify areas that may be of concern (e.g. a lump was felt during physical examination).

The developed mammography films are then interpreted by a radiologist, who compares the new images of a woman's breast to each other and to previous mammograms a woman has had. The radiologist will look for shadows and patterns of tissue density to detect any abnormalities.

A mammogram is like a fingerprint; the appearance of the breast on a mammogram varies tremendously from woman to woman, and no two mammograms are alike. It is extremely helpful for the radiologist to have films (not just the report) available from previous examinations for comparison purposes. This will help the doctor to recognize small changes that occur gradually over time and detect a cancer as early as possible.

Common Uses for the Test

Mammography is used to aid in the diagnosis of breast diseases in women.

Screening mammography can assist your physician in the detection of disease even if you have no complaints or symptoms.

Initial mammographic images themselves are not always 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 mammography is used to evaluate a patient with abnormal clinical findings—such as a breast lump or lumps—that have been found by the woman or her doctor. Diagnostic mammography may also be done after an abnormal screening mammography in order to determine the cause of the area of concern on the screening exam.

Risks and Benefits

Benefits:

Imaging of the breast improves a physician's ability to detect small tumors. When cancers are small, the woman has more treatment options and a cure is more likely.

The use of screening mammography increases the detection of small abnormal tissue growths confined to the milk ducts in the breast, called ductal carcinoma in situ (DCIS). These early tumors cannot harm patients if they are removed at this stage and mammography is the only proven method to reliably detect these tumors.

Risks:

The effective radiation dose from a mammogram is about 0.7 mSv, which is about the same as the average person receives from background radiation in three months. Federal mammography guidelines require that each unit be checked by a medical physicist every year to ensure that the unit operates correctly.

Women should always inform their doctor or x-ray technologist if there is any possibility that they are pregnant.

False Positive Mammograms. Five percent to 15 percent of screening mammograms require more testing such as additional mammograms or ultrasound. Most of these tests turn out to be normal. If there is an abnormal finding a follow-up or biopsy may have to be performed. Most of the biopsies confirm that no cancer was present. It is estimated that a woman who has yearly mammograms between ages 40 and 49 has about a 30 percent chance of having a false-positive mammogram at some point in that decade and about a 7 percent to 8 percent chance of having a breast biopsy within the 10-year period. The estimate for false-positive mammograms is about 25 percent for women ages 50 or older.