In recent years, the media occasionally report the news that some celebrities or public figures passed away due to breast cancer, which makes many women start to pay attention to the ultrasound examination of breast. What should I do after finding a breast nodule? A breast nodule is usually a disease in which a lump is created inside the breast tissue due to structural changes. After finding a breast nodule, do not panic first. This is because lobular hyperplasia, breast fibroadenoma, breast papilloma, breast cyst, mastitis and breast cancer can all manifest as breast lumps. Patients can first identify the benignity or malignancy of breast lumps by means of breast ultrasound, mammography and breast MRI. For women around the age of menopause, if a painless lump is found in the breast, it should be taken seriously. Because of its convenience and non-invasiveness, breast ultrasonography, together with mammography, is known as the “golden combination” and is currently recognized as the most common and effective means of screening for breast nodules. However, because mammography is less diagnostic for Asian women with dense breasts and has some radiation exposure, it is not recommended by the American Cancer Society for women younger than 35 years of age. Ultrasound examination of the breast has the following advantages: 1. It is radiation-free and non-invasive, and is also suitable for women during pregnancy and lactation; 2. It is of great value in identifying cystic or solid breast tumors; 3. Nowadays, the Breast Imaging Reporting and Data System (BI-RADS) developed by the American College of Radiology (ACR) has been applied to the ultrasound diagnosis of breast nodules. The BI-RADS is divided into grades 0-6: Grade 0: Incomplete evaluation and needs to be combined with other imaging examinations to make a final evaluation; Grades 1-3: Tendency to be benign and requires regular follow-up; Grade 4: (4a, 4b, 4c) Suspicious malignant lesions and should be considered for puncture biopsy; Grade 5: Almost certainly malignant lesions and appropriate measures should be taken by breast surgery; Grade 6: Is pathologically diagnosed as malignant. Nowadays, new ultrasound techniques, such as ultrasonography, elastography, and automated full-volume breast scan imaging, can also provide richer information for the diagnosis and differential diagnosis of breast nodules.