A chest x-ray is a painless, noninvasive test that creates pictures of the structures inside your chest, such as your heart, lungs, and blood vessels. "Noninvasive" means that no surgery is done and no instruments are inserted into your body.
This test is done to find the cause of symptoms such as shortness of breath, chest pain, chronic cough (a cough that lasts a long time), and fever.
X-rays are electromagnetic waves. They use ionizing radiation to create pictures of the inside of your body.
A chest x-ray takes pictures of the inside of your chest. The different tissues in your chest absorb different amounts of radiation.
Your ribs and spine are bony and absorb radiation well. They normally appear light on a chest x-ray. Your lungs, which are filled with air, normally appear dark. A disease in the chest that changes how radiation is absorbed also will appear on a chest x-ray