A chest X-ray is one of the most common imaging tests in the world, and it takes only a few seconds. It can quickly show pneumonia, fluid on the lungs or a collapsed lung, but it also has limits worth knowing.
Imagine a cough that will not shift after three weeks, with a fever and breathlessness. Your healthcare provider sends you for a chest X-ray “just to check”. Within a day, you know whether it is pneumonia.
What a chest X-ray shows
- The lungs, including infection such as pneumonia, and collapsed areas
- Fluid around the lungs (pleural effusion)
- Air around the lungs (pneumothorax, a collapsed lung)
- The size and shape of the heart
- Signs of heart failure, such as fluid in the lungs
- Some lung masses or nodules
- Broken ribs and the position of tubes or lines after procedures
Common reasons for a chest X-ray
- A cough lasting more than three weeks, or coughing up blood
- Breathlessness or chest pain
- Fever with suspected chest infection
- Suspected tuberculosis
- Before some operations or for some job or visa medicals
- Checking the position of medical devices such as central lines or feeding tubes
What happens
You will usually be asked to remove clothing and jewellery from the waist up and wear a gown. You stand with your chest against a plate and your hands on your hips or around the plate, then take a deep breath and hold it for a few seconds while the X-ray is taken. A side view is sometimes taken too.,For people who are unwell in hospital, a portable X-ray can be taken in bed. The images are less detailed but still useful.
How safe is it?
A chest X-ray uses a very small dose of radiation, roughly equivalent to a few days of the natural background radiation we are all exposed to from the environment. The risk from a single chest X-ray is extremely low.,Healthcare providers still only order X-rays when they are needed, and staff stand behind a screen because they take many X-rays every day.
Pregnancy
Tell the radiographer if you are or might be pregnant. A chest X-ray exposes the baby to very little radiation, and when it is needed, the benefit usually outweighs the small risk. Protective measures may be used, and other tests may be considered first.
What a chest X-ray cannot show well
Chest X-rays are a good first test but can miss small lung nodules, early lung cancer, some cases of pulmonary embolism and problems hidden behind the heart or ribs. If symptoms continue despite a normal X-ray, your healthcare provider may recommend a CT scan or other tests.
Common terms in a report
- Consolidation: an area of lung filled with fluid or pus, often pneumonia
- Effusion: fluid around the lung
- Pneumothorax: air outside the lung, causing collapse
- Cardiomegaly: enlarged heart shadow
- Atelectasis: a small area of lung that is not fully inflated
- Nodule: a small rounded spot that may need follow-up
- No acute abnormality: nothing urgent seen
Getting your results
A radiologist or reporting radiographer reviews the images and writes a report, usually within a few days, or much faster in emergencies. Your healthcare provider will explain the results. If a follow-up X-ray is advised, for example six weeks after pneumonia in some adults, make sure it is booked.
Chest X-ray and lung cancer
A chest X-ray is often the first test for symptoms such as a persistent cough, coughing up blood, unexplained weight loss or breathlessness. It can show some lung cancers, but small or early cancers may not be visible.
In some countries, people at higher risk, usually current or former heavy smokers in older age groups, are offered lung cancer screening with low-dose CT scans, which are much better at finding early cancers than X-rays. Ask your healthcare provider whether a screening programme applies to you.
X-rays for tuberculosis
Chest X-rays play an important role in finding tuberculosis (TB), especially in countries where TB is common and for people screened before travel or migration. TB can cause typical changes in the upper parts of the lungs. A suspicious X-ray is followed by tests on sputum (phlegm) to confirm the diagnosis, because X-ray changes alone are not enough.
Children and chest X-rays
Children are more sensitive to radiation than adults, so X-rays are only used when they will help make a decision about care. Doses are adjusted for size, and parents can usually stay with their child, wearing a protective apron. Holding still for a moment is the hardest part for young children, and the radiographer will help.
Questions to ask
- Why do I need this X-ray?
- Who will tell me the results, and when?
- Will I need a follow-up X-ray or other scans?
- What should I do if my symptoms get worse before I hear back?
Frequently asked questions
Do I need to prepare?
No special preparation is needed.
Can children have chest X-rays?
Yes, when needed. Doses are adjusted for children.
Will I need a CT scan as well?
Only if the X-ray or your symptoms suggest a CT would add useful information.
Can I have an X-ray while breastfeeding?
Yes. X-rays do not affect breast milk.
But my X-ray was normal and I still feel unwell
Tell your healthcare provider. A normal X-ray does not rule out every cause of symptoms, and further tests may be needed.
Your next step: If you have had a cough for more than three weeks, or are coughing up blood, see a healthcare provider.
Related: Tuberculosis symptoms · Signs of pneumonia
Sources: UK Health Security Agency radiation guidance, Royal College of Radiologists, Radiological Society of North America (RadiologyInfo), World Health Organization.
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