Human: My doctor says I have to have a mammogram. What is a mammogram and why is it so important? Assistant: 
A mammogram is an X-ray of the breast. It’s used to detect any abnormalities in the breast tissue that could be signs of cancer. Mammograms are recommended for women over the age of 40, but they can also be done earlier if you have risk factors such as a family history of breast cancer or previous breast biopsies. The goal of a mammogram is to find early signs of cancer before they can spread throughout the body.