Mammography is one of the best tests available for diagnosing breast disease and has several unique values: 1) It is safe, non-invasive, and the images can be compared before and after. 2. It can often detect nodules that cannot be reached by physicians, namely the so-called “occult breast cancer” and very early in situ cancer. 3.It can identify benign lesions and malignant tumors of the breast more reliably. 4.Determine the location of the tumor, the extent of infiltration, the presence of multiple cancer foci and the condition of the contralateral breast. 5.To precisely locate the non-palpable breast nodes and guide the precise excision of surgery.