UKHSA updates its patient dose tables and UK background radiation figures
On 28 September 2026 the UK Health Security Agency (UKHSA) revised the UK average radiation figures on two pages that are widely used to explain X-ray doses to patients and students.
What's new
UKHSA's patient dose information table lists typical effective doses for X-ray, CT and nuclear medicine examinations alongside an "equivalent period of natural background radiation". It now uses a UK average natural background of 2.1 mSv per year, down from 2.2 mSv, and notes that regional averages range from about 1.5 to 7.5 mSv a year.
On the same day, UKHSA's dose comparisons page changed its figure for the average total annual dose received in the UK, from all sources including medical exposures, from 2.7 mSv to 2.6 mSv. These are two different quantities: 2.1 mSv is natural background only, while 2.6 mSv is the total.
Typical examination doses in the patient table include about 0.02 mSv for a single PA chest film (about 3 days of background), 0.7 mSv for an abdominal film (about 4 months), 1.3 mSv for the lumbar spine (about 7 months) and 8 mSv for CT chest. The dose comparisons page gives different values for some of the same examinations (0.014 mSv for a chest X-ray, 6.6 mSv for CT chest), because typical doses depend on the survey and technique behind them.
What it means for learners
- Quote the right baseline. If you compare an X-ray with "days of background radiation", the UKHSA patient table now assumes 2.1 mSv a year. Do not mix it up with the 2.6 mSv total annual dose.
- Typical doses are ranges, not fixed numbers. Two UKHSA pages give different chest X-ray and CT chest values, so present doses as approximate, as the radiation dose and protection module does.
- The patient conversation is unchanged. A chest X-ray is still roughly a few days of natural background. Justification under IR(ME)R, not the size of the number, decides whether an exposure should happen.
Source
- UK Health Security Agency. Patient dose information: guidance (Medical radiation: patient doses). GOV.UK, updated 28 September 2026. gov.uk: patient dose information
- UK Health Security Agency. Ionising radiation: dose comparisons. GOV.UK, updated 28 September 2026. gov.uk: ionising radiation dose comparisons
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For education only. Not a substitute for a formal report, senior review or your local policy. Never use this page to make decisions about a real patient.