Should you worry about having X-rays?
It’s over a century since X-rays were discovered and first allowed doctors to look inside a living human body. Today, the NHS carries out more than 22 million a year in England alone, and millions more are performed by dentists.
Most of us have had an X-ray for fractured bones or to allow the dentist to examine our teeth. They are also used in CT scans to build up detailed images of our bodies.
X-rays are a type of high-energy radiation that can easily pass through most body tissues, like muscle and fat, but they are blocked by denser material like bone. When the body is exposed to an X-ray, the skeleton casts a ‘shadow’ and this can be picked up by a detector.
However, the very properties that make them useful for seeing inside the body, are also what make them harmful. As they pass through us, X-rays can damage some of our cells, by causing changes in our DNA that have been linked to an increased risk of cancer.
We’ve been aware of the risks since the 1950s, and the strength, quantity and duration of your exposure to radiation are now controlled within strict guidelines.
So how much harm do X-rays really cause us?
The dose we receive from an X-ray can be compared to the background radiation that we’re exposed to every day in our environment. This includes radioactive radon gas from the ground, cosmic rays from space and radiation from some foods.
These forms of background radiation are not harmless, but their effects are virtually unnoticeable.
So how powerful are medical X-rays in comparison?
During the average Transatlantic flight we are exposed to more than three times the level of radiation we would receive from a chest X-ray.
If we were to have two dental X-rays a year every year of our life, it would raise our chance of developing cancer by only around one hundredth of one per cent.
Some forms of X-ray are more powerful than others, such as CT scans, and some of us have complex medical conditions that require a large number of X-rays over our lifetime.
Multiple X-rays have a cumulative effect on the body, so the more you have, the greater the amount of cell damage over time. So, when possible, your doctors will recommend other types of imaging that do not use radiation, for example ultrasound or magnetic resonance imaging (MRI) scanning.
In some cases an X-ray is the best way to do the job, so you and your doctor will need to balance the risks and benefits of having one. If you are concerned, tell your doctor about any previous X-rays you have had.
Ultimately X-rays are associated with a tiny risk of increasing the likelihood of cancer, but in medicine the benefits hugely outweigh the risks.