A chest x-ray uses high-energy electromagnetic radiation to take pictures of the chest, lungs, heart, larger arteries, ribs and diaphragm. Even small structures such as blood vessels appear on a chest x-ray. The image of your chest appears on a film called a radiograph, which shows structures inside the body as light or dark depending on absorption rates of the different tissues. Dense materials such as bone are white, while fat and muscle appear as varying shades of gray. The lungs appear dark because they are filled with air.
Chest x-rays may be used to diagnose, stage and treat lung cancer. In low doses, x-rays can be used to construct images of structures inside the body to detect and stage a tumor. In higher doses, x-rays can be used in radiation therapy to help destroy cancerous cells in the body.
Chest x-rays also may be done if you have tuberculosis or other diseases of the chest or lungs, or if you experience any of the following symptoms:
- Chronic cough
- Chest injury
- Chest pain
- Coughing up blood
- Difficulty breathing
Doctors use chest x-rays to help diagnose pneumonia, heart failure and lung tissue scarring, in addition to lung cancer. Chest x-rays help doctors determine how well treatments are working and they are often done before surgery so doctors can see the structures in the chest in advance.
You should not feel any discomfort during a chest x-ray, though the film plate may feel cold. Before the test, a technician may place a lead apron on certain parts of your body to prevent unnecessary radiation exposure. Overall, radiation exposure from a chest x-ray is low. For the test, you will stand in front of an x-ray machine and will be asked to hold your breath briefly while the x-ray is taken. A chest x-ray is done relatively quickly.