It is well recognized that computed tomography (CT) imaging has become a cornerstone of diagnostic evaluation in emergency medicine, particularly for complex presentations such as trauma, cerebrovascular accidents, intracranial injuries, and abdominal pain.¹ However, the increasing reliance on CT has raised important ethical considerations related to the principle of non-maleficence, given concerns about excessive radiation exposure.^2-4 A recent JAMA Internal Medicine study by Smith-Bindman et al.⁵ adds valuable data to this ongoing discussion.

Using CT imaging data from 2018 to 2020, Smith-Bindman and colleagues performed an analysis of patient demographics, scanned body regions, and diagnostic indications to estimate radiation doses per scan. They subsequently developed a model projecting the number of cancers potentially induced by CT radiation exposure. Based on 93 million CT scans performed in the United States in 2023, their model estimated approximately 103,000 new cancers attributable to CT imaging, roughly 5 percent of all annual cancer diagnoses.⁵

The authors further stratified their projections by body region, cancer type, sex, and age group, including pediatric patients. While acknowledging limitations, such as reliance on risk estimates derived from atomic bomb survivor data and potential overestimation in populations with reduced life expectancy, the study nevertheless highlights a critical issue warranting broader reflection.

Although clinicians are generally aware that plain radiographs (X-rays) expose patients to ionizing radiation, they may not be aware that the magnitude of exposure from CT is far greater: The average effective dose for a chest X-ray is 0.1 mSv compared with 7 mSv for a chest CT.⁶ For context, the average American receives approximately 6.2 mSv annually from background radiation.⁷ These are facts of which some clinicians may not be aware.⁸ This further emphasizes the significance of Smith-Bindman et al.’s retrospective modeling study, as it enables imperative reflection on current clinical practices.

The study’s projections are particularly relevant to emergency medicine, where CT utilization continues to rise. A 2019 survey of over 1,000 U.S. emergency departments reported CT use in 27 per 100 patient encounters, nearly equivalent to the use of electrocardiography (28 per 100 patients).⁹ With CT rates steadily increasing over time,^1,9 and approximately 19 percent of ED visits leading to inpatient admission, where additional imaging may occur,^10,11 emergency clinicians should view these findings as a call for vigilance.

Another factor to consider is that certain populations have historically relied more heavily upon EDs due to financial and other barriers preventing their access to primary care.^12-14 This may disproportionately expose these groups to excessive radiation, further exacerbating existing health disparities.