The main difference between low-dose CT and normal CT is the difference in scanning conditions. The main difference between low-dose CT is that the milliampere-second and kilovolt values in the scanning conditions are relatively low, which reduces the radiation dose. Because there is radiation in CT, current examinations are dedicated to reducing the radiation dose without compromising image quality. Therefore, as long as the diagnostic criteria can be met, low-dose CT should be chosen as much as possible; ordinary CT is a conventional scan, and the image quality of such a scan is best according to the conventional scanning conditions. At present, patients with early lung cancer screening are examined by low-dose CT, and the trend of future examinations is to choose low-dose scans as much as possible.