Sharp rise in CT scans prompts call for new safeguards on radiation exposure

BMJ 2014; 349 doi: (Published 18 August 2014) Cite this as: BMJ 2014;349:g5218
  1. Matthew Limb
  1. 1London

A group of experts has called for extra safeguards to protect people from radiation exposure, given a “dramatic” recent rise in the use of computed tomography (CT) scanning.

Hospitals in England carried out almost five million CT scans in 2012-13, compared with just over one million in 1996-97, the Committee on Medical Aspects of Radiation in the Environment said.1 The committee chair, Alex Elliot, said that the latest data for 2013-14 showed a further 13% rise in use this year and that it showed no sign of “plateauing.”

He said that CT scans made up a big proportion of the overall medical exposure to radiation in the United Kingdom, so their rising use was a concern in terms of patients’ overall radiation exposure. A key concern was that their use in children was rising quickly, he noted, because children are more sensitive to ionising radiation than adults and will live longer with the potential risks. The number of UK children undergoing CT scans rose from 25 000 in 1993 to 48 000 in 2002, and this has since doubled to around 100 000.

CT scanning has been shown to increase a child’s risk of brain cancer and leukaemia, and the increased risk is dose dependent.2 “An abdominal CT scan is the highest radiation dose,” said Elliot. “If you were to carry out 2000 abdominal CT scans, statistically you would cause one case of cancer.”

However, the committee emphasised that the benefits of CT scans outweighed their potential risks when used appropriately and carried out safely. The committee published a report on 14 August, which was commissioned by the Department of Health and contained seven recommendations for a more “proactive approach” to CT scanning to better protect patients.

The committee said that it should be mandatory for hospitals to report their CT scan use and dose levels to Public Health England, to check how they align with diagnostic reference levels (DRLs). DRLs were introduced to support the control and periodic reduction of radiation doses resulting from diagnostic procedures.

Elliot said, “If a hospital or radiology department is continually exceeding those DRLs, somebody somewhere should be asking why.” He added that a full assessment of a patient’s risk from exposure could not currently be made because hospitals did not provide data on CT dosing levels voluntarily. “If we don’t know how much radiation people were exposed to, we can’t work out what the risk of that radiation was,” he said.

Several of the report’s recommended measures to minimise radiation exposure included ensuring the appropriateness of referrals and “optimisation” of scanning procedures and equipment. Hospitals should buy CT scanners with dose reduction features and make sure that radiologists and radiographers know how to adjust them to set appropriate dose levels for individual patients, the committee said. Furthermore, scanning should seek to produce the image quality necessary to answer specific clinical questions, rather than aim to provide the most detailed image possible.

The committee said that some genetic conditions were associated with an increased susceptibility to ionising radiation and that more research was needed to find out who may have a higher risk.

Professional bodies and medical and scientific societies should work to increase clinical staff’s understanding of all potential risks to patients from ionising radiation, and not just the dose received from CT scans, the committee added, and hospitals should appoint a team of “radiation protection champions” to support efforts to reduce radiation doses.


Cite this as: BMJ 2014;349:g5218


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