Currently recognized breast imaging methods mainly include mammography, ultrasonography, MRI, and its different methods have their own characteristics and indications, so now I will give you a detailed introduction. 1, mammography: based on the different relative absorption rate of different tissues for X-ray, it can be distinguished in the image. x-ray photography is sensitive to calcification in the breast, and can find very small diameter microcalcification. Breast ultrasonography: Breast ultrasonography is painless, radiation-free, and can be repeated several times in a short period of time, and it is suitable for women of any age and any physiological period (including pregnancy and lactation). Ultrasonography is more accurate in determining the nature of lumpy lesions (cystic or solid), and is helpful in detecting dense breast lumps that are difficult to show on X-ray. However, ultrasound is not clear for small calcified foci; it is difficult to diagnose tiny lumps in hyperplastic glands and special type of breast cancer; the image features of some benign and malignant diseases overlap; it is highly dependent on the operator’s skills and difficult to conduct retrospective analysis. 3, Breast MRI: MR is widely used in the diagnosis of breast diseases in recent decades because of its high soft tissue resolution and no radiation. Dynamic enhancement MRI can not only show the morphological information of lesions, but also provide functional information such as lesion blood supply, water molecule diffusion, cell membrane choline metabolism, etc., which is a more sensitive means of breast imaging. However, it is more expensive and not applicable to breast screening under the current situation. 4. Breast nuclear medicine examination: PET-CT makes use of the metabolic differences between normal tissues and tumor tissues for tumor diagnosis, which has high diagnostic sensitivity and specificity, and it can evaluate the tumor lymph node metastasis and systemic metastasis (N staging and M staging) and provide the basis for the selection of treatment plan. However, specific imaging agents for breast cancer have not yet been applied in the clinic.