Commonly used breast examinations: infrared (now largely obsolete) ultrasound; mammogram (commonly known as mammogram); breast MRI. Selection of examinations for each age group: 20 to 35 years old (1) Mammography once every 1-3 years. 35 to 49 years of age (1) 1 mammogram every year. (2) Recommended in conjunction with clinical physical examination. (3) Recommended for dense breasts in conjunction with color ultrasound, and breast MRI if necessary. 50～69 years old (1) 1 mammogram every 1-2 years. (2) Recommended in combination with clinical physical examination. (3) Recommended in conjunction with color ultrasound for dense breasts, and breast MRI if necessary. 70 years of age or older (1 mammogram every 2 years). (2) Recommended in combination with clinical physical examination. (3) Recommended to be combined with color ultrasound for dense breast, and breast MRI if necessary. People at high risk of breast cancer It is recommended that people at high risk of breast cancer be screened in advance (before the age of 35 years), and the intervals between screenings are recommended to be once every 6 months. In addition to the application of clinical physical examination, color ultrasound, and mammography commonly used in the general population, the screening means can be applied to the application of imaging means, such as MRI. Definition of high-risk groups for breast cancer (1) People with obvious genetic predisposition to breast cancer. (2) Patients with previous moderate to severe atypical hyperplasia of breast ducts or lobules or lobular carcinoma in situ. (3) Patients with previous history of chest radiotherapy.