About breast screening - Mammography and radiation risk
Is there a risk of radiation?
We use mammography (breast x-rays) to find breast cancer. This means that radiation is passed through your breast to form a picture. Radiation can cause cancer, but the risk from having a breast x-ray is very low.
The benefit far outweighs the radiation risk.
The number of lives saved by finding and treating breast cancer is much greater than the number of lives that may be lost because of cancer caused by radiation.
How do we minimise the risk?
The amount of radiation is called a dose. We check our equipment to make sure that it gives the best balance between the dose and the quality of the breast x-ray for each individual breast that is imaged. Doses from all our equipment comply with UK standards. We minimise unnecessary radiation dose by ensuring that very few breast x-rays need to be repeated.
How big is the risk?
The risk of a cancer caused by radiation from having a mammogram is between 1 in 49,000 to 1 in 98,000 per visit.
How does the risk compare with the benefit?
It is estimated that for every cancer caused by radiation from having a breast x-ray, around 400-800 breast cancers are found. Research has shown that breast screening programmes save around 1,300 lives in the UK each year, as early detection of cancers leads to improved survival rates.
How does the dose from mammography compare with other sources of radiation?
The amount of radiation received during a breast x-ray is very small. Things that expose you to about the same radiation dose and risk as a breast x-ray include:
- A few months of natural background radiation (or a few weeks in Cornwall)
- A few long haul flights
What is the effect of having many x-ray examinations?
Each individual x-ray examination carries its own level of risk. To estimate the effect of having many examinations, the risks are simply added together. It does not make any difference whether the examinations are all done in one day or spread over many years. The total risk is the same.
What about mammography during pregnancy or breast feeding?
In mammography, the radiation is directed only at your breast. The risk to a baby in the womb is negligible. However, if you think you may be pregnant or are breast feeding and have any concerns about the risk, please talk to us before having your breast x-ray.
Sources of information
- Radiation Risk with digital mammography in breast screening
- Exposure to ionising radiation from medical Imaging safety advice
- Ionising radiation dose comparisons
Page last reviewed: 26th January 2026