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What Is a Chest X Ray?

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.

Overview

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.

Chest X Ray

Figure A shows a cross-section of a chest. Figure B shows an x-ray image of a chest. Roll your mouse over the terms on right side of the x-ray image to highlight the internal structures of the chest on both figures.

Chest x rays help doctors diagnose conditions such as pneumonia (nu-MO-ne-ah), heart failure, lung cancer, lung tissue scarring, and sarcoidosis (sar-koy-DO-sis). Doctors also may use chest x rays to see how well treatments for certain conditions are working. Also, doctors often use chest x rays before surgery to look at the structures in the chest.

Chest x rays are the most common x-ray test used to diagnose health problems.

Outlook

Chest x rays have few risks. The amount of radiation used in a chest x ray is very small. A lead apron may be used to protect certain parts of your body from the radiation.

A chest x ray gives out a radiation dose similar to the amount of radiation you're naturally exposed to over 10 days.




Other Names for a Chest X Ray

  • Chest radiography (RA-de-OG-ra-fee)
  • CXR



Who Needs a Chest X Ray?

Doctors may recommend chest x rays for people who have symptoms such as shortness of breath, chest pain, chronic cough (a cough that lasts a long time), or fever. The test can help find the cause of these symptoms.

Chest x rays look for conditions such as pneumonia, heart failure, lung cancer, lung tissue scarring, or sarcoidosis. The test also is used to check how well treatments for certain conditions are working.

Chest x rays also are used to evaluate people who test positive for tuberculosis (tu-ber-kyu-LO-sis) exposure on skin tests.

Sometimes, doctors recommend more chest x rays within hours, days, or months of an earlier chest x ray. This allows them to follow up on a condition.

People who are having certain types of surgery also may need chest x rays. Doctors often use the test before surgery to look at the structures inside the chest.




What To Expect Before a Chest X Ray

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. Before the test, you'll be asked to undress from the waist up and wear a gown.

You also may want to avoid wearing jewelry and other metal objects. You'll be asked to take off any jewelry, eyeglasses, and metal objects that might interfere with the x-ray picture. Let the x-ray technician (a person specially trained to do 
x-ray tests) know if you have any body piercings on your chest.

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.




What To Expect During a Chest X Ray

Chest x rays are done at doctors' offices, clinics, hospitals, and other health care facilities. The location depends on the situation. An x-ray technician oversees the test. This person is specially trained to do x-ray tests.

The entire test usually takes about 15 minutes.

During the Test

Depending on your doctor's request, you'll stand, sit, or lie for the chest x ray. The technician will help position you correctly. He or she may cover you with a heavy lead apron to protect certain parts of your body from the radiation.

The x-ray equipment usually consists of two parts. One part, a box-like machine, holds the x-ray film or a special plate that records the picture digitally. You'll sit or stand next to this machine. The second part is the x-ray tube, which is located about 6 feet away.

Before the pictures are taken, the technician will walk behind a wall or into the next room to turn on the x-ray machine. This helps reduce his or her exposure to the radiation.

Usually, two views of the chest are taken. The first is a view from the back. The second is a view from the side.

For a view from the back, you'll sit or stand so that your chest rests against the image plate. The x-ray tube will be behind you. For the side view, you'll turn to your side and raise your arms above your head.

If you need to lie down for the test, you'll lie on a table that contains the x-ray film or plate. The x-ray tube will be over the table.

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 steps help prevent a blurry picture.

Although the test is painless, you may feel some discomfort from the coolness of the exam room and the x-ray plate. If you have arthritis or injuries to the chest wall, shoulders, or arms, you may feel discomfort holding a position during the test. The technician may be able to help you find a more comfortable position.

When the test is done, you'll need to wait while the technician checks the quality of the x-ray pictures. He or she needs to make sure that the pictures are good enough for the doctor to use.




What To Expect After a Chest X Ray

You usually can go back to your normal routine right after a chest x ray.

A radiologist will analyze, or "read," your x-ray images. This doctor is specially trained to supervise x-ray tests and look at the x-ray pictures.

The radiologist will send a report to your doctor (who requested the x-ray test). Your doctor will discuss the results with you.

In an emergency, you'll get the x-ray results right away. Otherwise, it may take 24 hours or more. Talk with your doctor about when you should expect the results.




What Does a Chest X Ray Show?

Chest x rays show the structures in and around the chest. The test is used to look for and track conditions of the heart, lungs, bones, and chest cavity. For example, chest x-ray pictures may show signs of pneumonia, heart failure, lung cancer, lung tissue scarring, or sarcoidosis.

Chest x rays do have limits. They only show conditions that change the size of tissues in the chest or how the tissues absorb radiation. 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 areas of cancer and blood clots in the lungs usually don't show up on chest x rays.

For these reasons, your doctor may recommend other tests to confirm a diagnosis.




What Are the Risks of a Chest X Ray?

Chest x rays have few risks. The amount of radiation used in a chest x ray is very small. A lead apron may be used to protect certain parts of your body from the radiation.

The test gives out a radiation dose similar to the amount of radiation you're naturally exposed to over 10 days.




Links to Other Information About Chest X Rays

Non-NHLBI Resources

Clinical Trials

 
August 01, 2010 Last Updated Icon

The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.