A mammogram is a picture of your breast taken with a safe, low-dose X-ray machine.

Your technologist will ask you to stand facing the mammography machine, and then place one breast at a time on a flat surface. Another flat surface — called a compression paddle — will gently be lowered into place to compress your breast.

Compression is necessary to spread out the breast tissue and to eliminate motion, which may blur the image. The compression may be uncomfortable, but shouldn't hurt. Compression usually lasts no more than a few seconds.

During this time, an X-ray beam comes from above and penetrates your breast tissue. The X-ray image is either created on a film cassette, located below your breast, or recorded digitally and stored in a computer.

Denser breast tissue, such as cancer or calcifications, appears bright and white, whereas less dense tissue, such as fat, appears dark or gray.

After the X-ray is complete, the compression will release and the technologist will change the angle of the machine. Again, the technologist will position your breast on the flat surface, gently lower the compression paddle and take one more X-ray. This process may be repeated again.

Following the procedure, the images are processed and interpreted by a radiologist. A final report is sent to your doctor.