How safe are x-rays

X-rays are used to image inside your body so that your clinician can make an accurate and informed diagnosis. X-rays are also used in CT scans, but not in MRI or ultrasound scans.

Any exposure to X-rays carries a potential risk of later developing cancer. The risk from almost all medical X-rays (including CT scans) is very small. The doses are actually comparable to the levels of natural background radiation which we are exposed to every day. A typical chest X-ray can also be compared to a similar radiation dose you may receive on an short flight. The decision to perform an X-ray is made by a qualified person who ensures that the exposure is justified. This means that the overall medical benefit for having the X-ray outweighs any potential risk.

Please inform the radiographer if you think you might be pregnant.

The table below shows the typical doses from x-rays and how they compare to other doses we commonly receive. The risk from these levels of dose are very small compared to the beneficial imaging information gained from carrying out the X-ray.

Source of Exposure Dose
Dental x-ray 0.005mSv
100g Brazil nuts 0.01mSv
Chest x-ray 0.014mSv
Transatlantic flight 0.08mSv
CT head scan 1.4mSv
UK average radiation dose 2.7mSv
USA average radiation dose 6.2mSv
CT chest scan 6.6mSv
Average annual radon dose in Cornwall 6.9mSv