What it is
An X-ray (also called a radiograph) takes a picture of the inside of your body using a small amount of radiation. Dense parts such as bone block most of the beam and look white, air-filled lungs look dark, and soft tissue shows in grey. The most common are X-rays of the chest and bones. A radiographer takes the picture, and a radiologist, a doctor who reads scans, studies it.
Why it is done
A doctor may ask for an X-ray to look for a broken bone after a fall or accident, or to find the cause of a cough that will not go, chest pain, fever or breathlessness. A chest X-ray can show signs of pneumonia, tuberculosis, fluid around the lung, a collapsed lung and heart failure. X-rays also help to find kidney stones.
What it helps with
How to prepare
Most X-rays need little preparation.
Do
- Take off jewellery and clothes with zips, poppers or hooks over the area
- Tell the radiographer if you are or might be pregnant, or are breastfeeding
- Tell them about your medicines, any allergy, and any earlier reaction to barium or dye
Do not
- Do not keep quiet about a possible pregnancy, even if you are not sure
- Do not eat or drink during the hours you were told to fast for a barium or dye test
- Do not stop any medicine unless the doctor tells you to
What happens
A standard X-ray goes like this:
- You remove metal items and, if needed, change into a gown.
- The radiographer places you standing, sitting or lying by the machine, and may cover other parts of your body with a lead apron.
- The radiographer steps behind a screen. You keep very still and, for a chest X-ray, breathe in and hold it.
- The picture is taken in a moment and you feel nothing. For a chest X-ray there is usually a second picture from the side.
Some X-rays follow a barium drink or an injection of dye, to show a part more clearly. Dye can cause a hot, flushed feeling and a metallic taste that pass quickly.
Afterwards
You can usually go straight back to your normal day. After barium or dye you may be asked to wait up to 30 minutes so the team can check for a reaction. A radiologist reads the pictures and the report goes to the doctor who asked for the test. You may hear the same day or at a later visit. If you have heard nothing after a few weeks, contact that doctor.
Risks and side effects
X-rays are generally very safe. The main risk is radiation: one X-ray gives a small amount, but the chance of cancer rises very slightly with the number of X-rays over a lifetime, so doctors ask for one only when it is likely to help. Children are more sensitive than adults.
If you are pregnant, tell the team first. They will weigh the benefit against the risk and may take extra care or choose another test. Barium or dye can cause breathing difficulty, dizziness or a rash, so tell staff at once if you feel unwell.
Results and what comes next
The doctor who asked for the X-ray explains the result. A broken bone or a shadow in the lung is often clear, but an X-ray is a flat picture that shows bones and lungs well and gives less detail of soft parts such as muscles and organs.
If it is normal but your symptoms continue, tell your doctor. A gives more detail, an scan uses sound waves and no radiation, and an suits soft parts such as the brain, spine and joints.
Questions to ask your doctor
Tick the ones you want answered and take them with you.
Common questions
Does an X-ray hurt?
No. You feel nothing while the picture is taken, and you only need to keep still. If you have an injury, getting into position can be sore, so tell the radiographer, who can help you.
Can I have an X-ray if I am pregnant?
Always tell the team before the X-ray if you are or might be pregnant. X-rays use radiation, so they will weigh the benefit against the risk, take extra care, or sometimes choose another test. Talk to your doctor before deciding to skip a test you were asked to have.
Is the radiation from an X-ray harmful?
The amount in one X-ray is small, and doctors only ask for one when the benefit is greater than the very small risk. The risk rises slightly with many X-rays over a lifetime, so it helps to tell your doctor about X-rays you have already had.
Is an X-ray the same as a CT scan?
No. A CT scan also uses X-rays, but it takes many pictures from different angles and builds them into detailed slices. It shows more than a standard X-ray, and it uses more radiation.