Key Points

• A chest x ray is a painless, noninvasive test that creates pictures of the structures inside your chest, such as your heart and lungs.
• 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.
• The test helps doctors diagnose conditions such as pneumonia, heart failure, lung cancer, lung tissue scarring, and sarcoidosis. Doctors also may use chest x rays to see how well treatments for health problems are working. Also, doctors often use chest x rays before certain types of surgery to look at the structures in the chest.
• X rays use ionizing radiation to create pictures of the inside of your body. Chest x ray is the most common x-ray test used to diagnose health problems.
• Chest x rays have few risks. The amount of radiation used in one chest x ray is very small. Sometimes, a lead apron may be used to protect certain parts of your body from the radiation.
• You don't have to do anything special to prepare for a chest x ray. However, you may want to wear a shirt that's easy to take off. You also may want to avoid wearing jewelry and other metal objects.
• Before the test, let your doctor know if you're pregnant or may be pregnant. In general, women should avoid all x-ray tests during pregnancy. Sometimes, though, having an x ray is important to the health of the mother and fetus. If an x ray is needed, the technician will take extra steps to protect the fetus from radiation.
• A chest x ray usually takes about 15 minutes. You'll sit, stand, or lie for the test. Usually, two views of the chest are taken. The first view is from the back. The second view is from the side. You'll need to hold very still while the pictures are taken. The technician may ask you to hold your breath for a few seconds. These measures help prevent blurry pictures.
• You usually can go back to your normal routine right after a chest x ray. In an emergency, you will get the x-ray results right away. Otherwise, it may take 24 hours or more. Talk to your doctor about when you should expect the results.
• Chest x rays do have limits. They only show conditions that change the size of a tissue or how radiation is absorbed. Also, chest x rays create two-dimensional pictures. This means that denser structures, like bone or the heart, may hide some signs of disease. Very small cancers and blood clots in the lungs usually don't show up on chest x rays. For these reasons, other tests may be needed to confirm a diagnosis.