Chest X-ray is not CT, chest X-ray and CT are two different examination methods. Chest X-ray is called fluorescence fluoroscopy, which is a commonly used X-ray examination method that utilizes X-rays to form images of the human body on a screen by using X-rays that have the properties of penetrability and fluorescence. Due to the difference in density and thickness of human tissues, when X-rays penetrate different tissues of the human body, the X-rays are absorbed to a different extent, resulting in different black and white contrasting images, which provide the basis for the doctor’s diagnosis. However, compared with CT, chest X-ray has certain limitations. CT has a higher resolution and can show subtle lesions, which are not easy to miss. At present, CT is still the first choice for lung examination, and it is not easy to miss the diagnosis of early lung cancer.