The Ministry of Health recently issued a notice requiring that health checkups should give priority to the use of ordinary radiography, CR (computerized radiography); areas with conditions, the recommended use of DR (digital radiography) instead of ordinary radiography and CR examinations. Health checkups should not use direct fluoroscopy; unless there are clear indications of disease risk, such as age over 50 years and long-term heavy smoking, cardiovascular disease risk assessment for medium to high risk, etc., should not use CT (computed tomography device); PET (positron emission tomography device), PET/CT, SPECT (single photon emission computed tomography device) and SPECT/CT (single photon emission computed tomography device) should not be used. B ultrasound and MRI have no radiation, while X-ray photography (including general radiography, CR and DR), CT and PET are used at the same site, and the amount of radiation is from largest to smallest: CT > PET > general radiography > CR > DR. Different parts of the body have their own preferred examination methods. Different examination methods have their own advantages, and there is a certain selection rule, but it is important not to (1) For superficial organs and abdominal organs, ultrasonography such as B-ultrasound is preferred; (2) For cranio-cerebral trauma, tumors of middle ear, nose and throat, bones and lungs, and some subtle bone trauma, CT examination is preferred and enhanced scan is added if necessary; (3) For brain tumors and lesions, spinal cord lesions, joint and ligament trauma and lesions, and some subtle hidden trauma, CT examination is preferred. (3) Magnetic resonance imaging (MR) is preferred for brain tumors and lesions, spinal cord lesions, joint and ligament trauma and lesions, and some subtle occult fractures. The “10-day rule”: no X-ray examinations within 10 days after menstruation. In special periods such as pregnancy, pregnancy preparation, and menstruation, women should refrain from X-ray examinations: (1) Mammography should not be done for women under 35 years of age; mammography should be prohibited for developing girls under 15 years of age; it should be used with caution for women who are pregnant or preparing for pregnancy; more than one mammogram a year before the age of 40 can do more harm than good; after 40 years of age, one to two mammograms a year can do more good than harm. It is now advocated to use ultrasound instead of X-ray mammography for screening, and only use X-ray or MR for further examination. (2) Women who are planning to get pregnant should wait for six months after X-ray examination before getting pregnant to minimize fetal malformations brought about by inadvertent medical examination. (3) Women of childbearing age should follow the “10-day rule”, i.e., no X-ray examination within 10 days after the onset of menstruation. (4) Hysterosalpingography should be performed 5-10 days after menstruation (some experts believe 3-7 days) and pregnancy should be avoided for 3 months after the test.