The difference between a chest radiograph and a chest CT is that a chest CT is a tomography scan and a chest film is an orthopantomogram or anteroposterior scan, and there is a big difference between the two in terms of resolution, clarity, and radiation exposure.
Chest radiograph is the basic imaging examination, it is X-ray scanning in the front and side position of a person, exposed on the film set up in the back to form an image, the image on the chest radiograph is the overlapping display of all the organs in the chest cavity, the resolution is relatively not as high as that of CT.
CT is a tomographic scan of the tissues and organs in the chest cavity, with each level of organ being visualized separately, with much higher resolution and clarity than chest film, but at the same time, the radiation dose of chest CT is much higher than that of chest film.
Therefore, for basic examination, such as physical examination, chest X-ray is usually done first, if chest X-ray is suspected of abnormalities, such as lung tumors, tuberculosis, or clinical symptoms are obvious, it is recommended to perform chest CT to improve the diagnosis rate.