Report Reveals Level of UK Exposure to X-Rays

Greater utilization of X-rays over the last 10 years, including a 140% increase in computed tomography (CT) scanning, has raised the yearly radiation dose the UK public receives, a health-protection agency research report has found.

Radiation scientists from the UK Health Protection Agency (HPA; London, UK) have estimated that about 46 million medical and dental X-ray examinations were carried out across the United Kingdom in 2008, an increase of 10% since 1997. Approximately two-thirds, 67%, of the procedures were performed in National Health Service (NHS) hospitals while 26% were performed by dentists.

The new HPA study revealed that the average annual radiation dose to each member of the public from all diagnostic X-rays has increased from 0.33 mSv in 1997, the last time a detailed frequency survey was completed, to 0.4 mSv. Most of the increase is due to the growth in the number of higher dose CT examinations. Medical X-rays remain the largest single artificial source of radiation exposure for the UK population. The average radiation dose from all sources of ionizing radiation remains about 2.7 mSv per person year and medical X-rays contribute 15% of this total.

Dr. John Cooper, director of the HPA's Center for Radiation, Chemical and Environmental Hazards, said, "Despite the increased use of diagnostic X-rays in medicine in the UK, the average dose to the population is still considerably lower than in comparable countries. This is because in the UK we carry out fewer X-ray examinations per head of population and because radiology departments are well managed by healthcare professionals.”

The survey also revealed that (1) CT scanning now accounts for around 68% of the dose to the UK public from all X-ray procedures. Approximately 1.4 million CT scans were performed in 1997 and 3.4 million in 2008--an increase of 140%. About 20,000 of these CT scans were performed on asymptomatic individuals as part of self-initiated health evaluation. (2) The NHS Breast Screening Program accounted for 2.03 million X-ray examinations in 2008, an increase of 45% since 1997 when 1.4 million examinations were performed. This increase is due to widening of the age range for screening to cover women aged 50-70, instead of those aged 50-64. (3) Dentists in the NHS and private practice carried out approximately 12 million diagnostic X-ray examinations in 2008, although their contribution to the UK radiation dose remains negligible since they are low dose procedures. (4) About 1.2 million X-ray examinations were taken in independent hospitals in 2008, an increase of 40% since 1997.

Dr. Cooper added, "We have previously drawn attention to the expanding use of CT scanning as an increasingly important source of exposure to ionizing radiation for the UK public, often replacing conventional X-ray examinations. This report confirms that trend. It is essential that we keep monitoring radiology practice in this way in support of patient safety.”

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UK Health Protection Agency