Mammography is the first choice and the easiest and most reliable non-invasive test for diagnosing breast diseases, with relatively less pain, simplicity, high resolution, good reproducibility, before-and-after comparison, and no limitation of age and body shape, etc. It is recognized as the best diagnostic method for routine clinical examination of breast cancer and preventive screening of breast cancer. Mammography can detect breast lumps that cannot be touched by doctors, especially for large breasts and fatty breasts, its diagnostic ability can be as high as 95%, and for stage T0 breast cancer (negative clinical diagnosis), which has a few tiny calcifications as its only manifestation, it can only be detected and diagnosed early with mammography.