Mammography is a special type of X-ray that is used for detailed images of the breast. Successful treatment of breast cancer depends on early diagnosis and mammography as a technique plays a major role in its early detection. It can show changes in the breast well before they are actually felt. Biopsy (sampling of tissue) of an abnormality may be done to further confirm if the tissue is cancerous or not.
What are the types of Mammography?
Mammography may be of two types:
Screening mammography: is done in a woman who has no complaints or symptoms of breast cancer. The goal is to detect cancer when it is still too small to be felt. Annual screening is recommended for women once they reach 40 years of age and in those with a family history of the disease.
Diagnostic mammography: is done in a woman who either has a breast complaint (a lump or a nipple discharge) or has had an abnormality found during screening mammography. It is more time consuming and expensive. It is used to determine the exact size and location of the abnormality and the surrounding tissues.
How is it performed?
During mammography a radiologist positions the patient. The breast is first placed on a special cassette and compressed with a pad made of soft plastic. This may be necessary to even out the breast thickness so that all of the tissue can be visualized. It also allows the use of a lower x-ray dose since a thinner amount of breast tissue is imaged.
The technologist stands behind the glass shield during the procedure. A beam of x-rays is passed through the breast to the film kept behind the plate, thus exposing the film. The woman may be asked to change position slightly between images to get a top to bottom and a side view. The examination process takes about half an hour.
What is the preparation needed for the procedure?
The patient should inform the doctor about any prior operation, use of hormones and family or personal history of breast cancer. It is advisable to avoid the procedure during or a week before the menstrual periods as the tenderness of the breasts may cause some discomfort. No deodorant, talcum powder or lotion should be worn under the arms on the day of the examination because this may appear as calcium spots on the x-ray film.
What are the benefits of Mammography?
Imaging of the breast helps in detecting tumours when they are small, for timely treatment and cure. Screening mammography helps in the detection of small abnormal tissue growths in the breast which may be easily removed completely when small.
What are its limitations?
Interpretations of mammograms may be difficult because a normal breast can appear differently for each woman. The radiologist may need to compare them from previous views to arrive at the correct diagnosis.
Breast implants may also impede accurate mammogram readings because silicon transplants are not transparent on x-rays and may block a clear view of the tissues behind them.