A chest x-ray produces an image of the inside of the chest showing the bones, heart and blood vessels.  Chest x-rays usually show the chest in two views: from the front and from the side. 

Although chest x-rays are not as sophisticated as some other diagnostic technologies, they provide information that cannot be obtained in an examination.  For instance, they can be valuable in initially evaluating:

• The size of the heart. An enlarged heart in which the heart muscles have grown larger due to overwork may suggest heart failure.  A small heart may suggest dehydration.
• The contour of the heart. Enlargement of a particular chamber or blood vessel may suggest heart failure or other abnormal functioning.  
• Blood flow to the lungs.  Blood flow that is more or less than normal to the lungs may suggest any of several heart defects or diseases – and indicate the need for more sophisticated tests.

Is Chest X-Ray Harmful?

Medical tests, including chest x-rays, should not be ordered unless they can provide information that is not available through simpler, safer methods.  While the exposure to radiation (including x-rays) is worthy of concern, the amount of radiation exposure in a chest x-ray is minimal.  A few x-rays a year is not believed to cause harm.