Mammography or mastography is an imaging technology used in the twentieth century for the detection of breast cancer and other breast abnormalities. Breast cancer is an abnormal growth in breast tissue that can spread to other parts of the body and cause death. Breast cancer affects about twelve percent of women worldwide. In the twenty-first century, mammography is one of the most accurate tools for screening and diagnosing breast cancer. A mammogram is the image created by sending low-level X-rays through breast tissue then filmed or a digital recorder captures the image, which a radiologist analyzes. A Senographe is the instrument used to create the mammogram to screen for breast cancer and other breast diseases. Mammography significantly decreased the number of deaths from breast cancer, but it can also give false positive results and cause physicians to over diagnose that may result in treatment for diseases women do not have.