Despite the significant progress in lung cancer research over the past decades, lung cancer is now the malignant tumor with the highest morbidity and mortality rate, accounting for 22.7% of all malignant tumor deaths in China, and its 5-year overall survival rate is only about 16%. The clinical status quo is that about 2/3 of lung cancer patients are already at advanced stage when they are diagnosed; in contrast, a large number of studies have shown that if lung cancer can be surgically removed at an early stage (especially stage I lung cancer), the prognosis of lung cancer will be significantly improved and the 5-year survival rate can be increased to about 80%. Therefore, how to improve the early diagnosis rate of lung cancer has become an important issue to improve the prognosis of patients. At present, in China, chest X-ray is still used for routine physical examination as the main means of lung cancer screening. Since the 1960s, researchers have been exploring the value and significance of chest radiographs for lung cancer screening, but the results have been less than satisfactory and have led to the gradual realization that this screening mode needs to be improved. In the 1990s, the introduction of spiral CT made LDCT (low-dose CT) screening a hot topic. However, although several studies have shown that LDCT can detect more nodules and cancers (including early-stage cancers) than regular chest films, its impact on lung cancer mortality has never been convincingly demonstrated. Therefore, the significance of LDCT for lung cancer screening has been controversial. The publication of the results of two recent 2011 studies (PLCO) cancer screening study and the National Lung Cancer Screening Study (NLST) report have had a profound impact on the way lung cancer is screened. The publication of the results of the PLCO study certainly provides strong evidence for the conclusion that “lung cancer screening with chest radiographs is ineffective,” despite the results of six randomized studies (mostly published in the 1980s) that did not provide clear evidence that chest radiograph screening reduced lung cancer mortality. The results of the National Lung Cancer Screening Study (NLST), conducted at 33 medical centers in the United States, were published in August 2011 in the New England Journal of Medicine (N Engl J Med 2011, 365: 395). The results put low-dose spiral CT screening (LDCT) in the spotlight: LDCT reduced lung cancer mortality by 20% compared to chest radiographs (p=0.004). the NLST study demonstrated the compelling conclusion that early detection reduces the risk of death from lung cancer and arguably represents a major step forward in the quest for lung cancer screening. As a result, the NLST study was hailed by the industry as “one of the few documents important enough to influence the history of lung cancer”; it was evaluated as one of the major advances in clinical oncology in 2011 by ASCO’s annual report; the NLST study was ranked second in Medscape’s Top 10 Research Advances that Changed Clinical Decisions in 2011; and the NLST study was ranked second in the Top 10 Research Advances that Changed Clinical Decisions in 2011. In November 2011, the National Comprehensive Cancer Network (NCCN) updated its guidelines to recommend the use of low-dose spiral CT for screening of individuals at high risk for lung cancer. The NLST study still has shortcomings: It should be noted that the NLST study explored lung cancer screening in a high-risk population (for those over 55 years old and at high risk of smoking). The current status quo is changing with the rapid increase in the number of non-smoking adenocarcinoma patients and the spectrum of lung cancer disease, with an increasing number of non-smoking, younger lung cancer patients, so how do we choose individual screening modalities? Moreover, smoking lung cancer patients have mostly central lesions, and in fact low-dose spiral CT may be more advantageous in detecting non-smoking adenocarcinoma of peripheral type. Therefore, Prof. Yilong Wu suggested that we should consider that the screening target of spiral CT should not be limited to the high-risk group of heavy smokers, but should be extended to those who are 40 years old and above, so that we can further reduce the mortality rate of lung cancer through “early detection and early intervention” strategy? CT of the chest is recognized as the most sensitive imaging method for lung lesions and has greatly improved the sensitivity and specificity of the detection of occupying lesions in the diagnosis of lung disease compared to X-ray plain films. However, the exposure dose is also 10 to 100 times higher than that of radiographs, a factor that seriously affects the widespread use of CT in chest examinations. In a study in the United States, based on the generally accepted relationship between radiation dose and cancer mortality, the significance of low-dose CT scanning of the chest: the radiation dose of conventional chest CT is approximately 100 times that of chest radiographs and 10 times that of mammograms. Compared with conventional CT scan conditions (180-220mA), low-dose CT of the chest reduces the dose of X-ray exposure to the patient by 80% or more; subjecting to 3 to 4 low-dose CT examinations of the chest is equivalent to the radiation dose of only 1 conventional CT of the chest, which greatly reduces the possible damage caused by X-rays to the human body. In the literature on lung cancer screening in the last decade, the focus has mostly been on the role of low-dose spiral CT in lung cancer screening, and it is believed that low-dose spiral CT significantly improves the detection rate of early lung cancer as well as non-calcified nodules. At the same time low-dose spiral CT for lung cancer screening still has some shortcomings: false-positive results in LDCT screening for lung cancer, overdiagnosis over chest radiograph screening, and additionally. Low-dose CT scan studies involve very many issues and must be multicenter studies; health administrative leaders and physicians in other departments should understand, cooperate, and support imaging physicians in the clinical application of low-dose most CT scan technology.