Lung cancer is the fastest growing malignant tumor in terms of incidence and mortality, and also one of the most threatening malignant tumors to the health and life of the population, according to the data released by the National Tumor Registry in 2014, in 2010, there were 600,59 million new cases of lung cancer in China (410,630,000 men and 180,960,000 women), ranking first in malignant tumors (first in men and second in women) and accounting for The incidence rate of lung cancer is 35,23% (male 23,03%, female 14,75%). The incidence rate of lung cancer is 35,23/100,000 (49,27/100,000 for men and 21,66/100,000 for women). During the same period, the number of lung cancer deaths in China was 480,660,000 (330,680,000 for men and 160,620,000 for women), accounting for 24,87% (26,85% for men and 21,32% for women) of the causes of death from malignant tumors. The mortality rate of lung cancer is 27, 93/100,000 (39, 79/100,000 for men and 16, 62/100,000 for women). In recent years, it has been clinically found that the incidence of lung cancer has a trend of low age, and the footsteps are getting closer and closer to us, and it is affecting our life more and more. The terrible thing about lung cancer is that it cannot be detected early and cannot be treated early, which also causes the existence of the phenomenon of poor treatment effect. cure rate. Many people know the necessity of early diagnosis and medical examination, but what kind of medical examination should be used, whether it is better to use chest X-ray or CT, and whether it will affect our body? Here, I suggest that low-dose CT (LDCT) is a more reliable method for medical checkups, as CT is 4-10 times more sensitive than conventional chest X-ray in detecting early lung cancer. Data from the International Early Lung Cancer Action Plan show that annual CT screening can detect 85% of stage I peripheral lung cancers, with an expected survival rate of 92% at 10 years after surgery. The U.S. National Lung Cancer Screening Trial also demonstrated that LDCT screening can reduce lung cancer mortality by 20%, making it the most effective lung cancer screening tool available. In China, CT is recommended for lung cancer screening in high-risk groups in the pilot technical guidelines for cancer screening and early diagnosis and treatment in a few regions. So what kind of people are at high risk? The risk assessment factors for lung cancer screening proposed in the National Comprehensive Cancer Network (NCCN) guidelines include smoking history (current and past), radon exposure history, occupational history, cancer history, family history of lung cancer, disease history (chronic obstructive pulmonary disease or tuberculosis), and smoke exposure history (passive smoking exposure). The NCCN guidelines suggest that lung cancer screening is necessary for this high-risk group of people: age 55 years or older, history of smoking ≥ 30 pack years, history of smoking cessation < 15 years or age ≥ 50 years, history of smoking ≥ 20 pack years, and several other risk factors such as passive smoking risk factors. Compared with chest radiography, CT can show lesion features, internal structures and surrounding related tissues more clearly, avoid lesions in hidden areas and overlapping areas (e.g., apical lung, rib-diaphragm angle, paraspinal, posterior heart, etc.) that are not easily observed by chest radiography, clarify whether there are masses or lymph nodes enlargement in the mediastinum and hilum, and facilitate clinical staging of lung cancer. The amount of irradiation received by patients during CT examination is measured to be within the safe and permissible range, so you do not have to worry about the side effects of damage to your body. If you or your family members, friends, neighbors or people you care about are in the high-risk group and have never taken a CT of the chest, it is necessary to suggest them to have a CT so that any problems can be dealt with in time and no problems can be kept as a baseline image for future comparison.