Preparation for a Mammogram

If your breasts are tender in the week before your period is due, you may wish to schedule your mammogram for another time in your cycle.

It is important that you do not wear any talcum powder or deodorant under your arms or on your breasts on the day of your examination.  These may appear on the mammographic films as calcium spots.  If at all possible, it is important that any previous mammogram films are obtained and made available to the radiologist on the day of your examination.  This allows comparison to be made between the previous examinations and may assist in diagnosing any changes that have occurred in the interim.

You will be asked to remove all clothing above the waist and will be given a loose fitting gown that opens at the front.

The Mammography Machine                                                           

The mammography unit is a rectangular box that houses the tube in which x-rays are produced.  This unit is used exclusively for x-rays of the breast with special accessories that allow only the breast to be exposed to the radiation.  Attached to the unit is a device that holds and compresses the breast and positions it so images can be obtained at different angles.                                                                                  

How Mammography Works

A specially qualified radiographer will perform your mammogram.  The breast is placed on a platform and compressed with a clear paddle.

It is necessary to compress the breasts in order to:

• Even out the breast thickness so that all of the tissue can be visualised.
• Spread out the tissue so that small abnormalities will not 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 eliminate blurring of the image caused by motion
• Reduce x-ray scatter to increase the sharpness of the image.

The technologist will go behind a glass shield while making the x-ray exposure, which will send a beam of x-rays through the breast to the film behind the plate, exposing the film.

You will ask to change positions slightly between images.  The routine views are a top-to-bottom view and a side view.  The process is repeated for the other breast.  The examination should take about half an hour.  When the mammogram is completed, you will be asked to wait while the Radiologist examines the images to determine if more are needed.

What does the procedure feel like? You will feel pressure on the breast as it is compressed.  Some women with sensitive breasts may experience discomfort.  If this is the case, schedule the procedure when your breasts are least tender.  The technologist will apply the compression in graduations.  Be sure to inform the technologist if pain occurs as compression is increased. If discomfort is significant, less compression will be used.	Click on photos for larger version
What are the benefits of Mammography? Mammography is able to detect small tumours.  When cancers are small the patient has more treatment options, and a cure is more likely. Mammography is able to detect small abnormal tissue growths in the milk ducts of the breasts, called ductal carcinoma in situ (DCIS).  These early tumours are not harmful if removed at this stage, and mammography is the only proven method to reliably detect these tumours.	Mammogram showing a breast cancer in the upper outer quadrant of the left breast	Magnification view of the same breast cancer

What are the limitations of Mammography?

Interpretations of mammograms can be difficult because a normal breast can appear differently for different women.  The appearance of a breast may be compromised by breast implants or if you have undergone previous breast surgery.  Because some breast cancers are hard to visualise the radiologist may want to compare the image with any previous examinations.

False Positive Mammograms: between five and ten percent of screening mammograms (mammograms in women who have no symptoms) results are abnormal and require more testing.  This may be further mammograms, ultrasound, fine needle aspiration or biopsy, and most of the follow up tests confirm that no cancer is present.