Early screening: 80% detection rate Statistics confirm that the global average 5-year survival rate of lung cancer is only 16%, while the average 5-year survival rate of early-stage (stage 1) lung cancer can reach 65%. Unfortunately, only 10% of lung cancer patients can be diagnosed and treated in the early stage, and most lung cancer patients only go to the hospital when symptoms such as hemoptysis and irritating dry cough appear, at which time, the disease has often developed to the middle and late stage, and the hope of cure is quite slim, and all treatments are palliative. It can be seen how important it is for lung cancer patients to be diagnosed at an early stage. At present, the clinical methods used for early diagnosis (screening) of lung cancer are X-ray chest examination, sputum cytology examination and low-dose spiral CT examination. Among them, low-dose spiral CT examination is the most effective large scale lung cancer screening tool nowadays. Through low-dose spiral CT examination, small lung cancers less than 1 cm in diameter can be detected, and the detection rate of early lung cancer is as high as 80%. Among the screened lung cancer patients, 80% to 90% can be cured by minimally invasive surgical resection without further radiotherapy and chemotherapy. Being radiated: lack of scientific basis In clinical practice, many people believe that the amount of X-ray radiation of CT will cause harm to human body, therefore, they are often reluctant to undergo CT examination. Indeed, the X-ray radiation dose of a chest CT is equivalent to 8-9 mS, which is 60-100 times of the X-ray dose of a plain chest X-ray (0.08-0.12 mS). The X-ray radiation dose is high and should not be used as a routine examination method. However, low-dose spiral CT highlights its advantages of fast scanning speed, low dose and high detection rate by reducing tube current, tube voltage and thin-layer reconstruction. At present, the technology of low-dose spiral CT is becoming more and more mature, and the radiation dose of scanning is significantly lower than that of conventional CT, which is only 1/4 of the dose, so it is a safe and effective means of lung cancer screening. A large international screening program has confirmed that annual low-dose spiral CT screening does not pose any health risk to the screened patients.