Doctors’ knowledge of patient radiation exposure from diagnostic imaging requested in the emergency department

To the Editor: At a time of apparent increasing concern over radiation exposure, the article by Keijzers and Britton1 unfortunately does not provide any perspective on the clinical necessity of the imaging investigations requested by emergency department doctors. It also contains inaccurate information.

Stating that “multidetector CT [computed tomography] scanners have the potential to expose patients to higher radiation doses”, and preceding it with “radiation doses per scan have increased by up to 40%”, is incorrect.

CT scanner manufacturers have for some time been producing scanners that have decreased radiation doses by incorporating various techniques,2 including iterative reconstruction (a reconstruction algorithm that corrects image data by using various models, thereby improving CT image quality while reducing radiation dose). The dosage reductions reported by major manufacturers and in the literature2 vary between 25% and 80%.

The efficacy of dose-reduction mechanisms and the concepts behind them have been outlined in numerous white papers and scientific articles, leading to the conclusion that “newer scanners have improved technology that facilitates lower patient doses”.3

In their seminal article, McCollough and colleagues caution that “alarmist articles” do the public a disservice. They also state that

While Keijzer and Britton’s research investigated emergency department doctors’ knowledge of radiation exposure, the sample was small, being restricted to one institution, and the study had other limitations, as acknowledged by the authors.1

The alarmist undertones have not been helped by the publication of articles in the lay press, such as “Doctors warned over X-ray risks”.4 The danger is that sensationalising the risks of CT scanning may lead to patients not undergoing scans that are clinically indicated, with consequent patient harm. The Royal Australian and New Zealand College of Radiologists (RANZCR) has issued a position statement on radiation dosage.5 As radiologists, we abide by the ALARA (as low as reasonably achievable) principle, and the RANZCR is actively pursuing ways of decreasing radiation exposure.5

In a clinical context, the risk from CT scans is small compared with health risks arising through other activities. Educating doctors about radiation exposure risks is crucial, but so is up-to-date information and common sense, devoid of sensationalism.