CT radiation exposure of emergency department patients before, during and after the COVID-19 pandemic.

OBJECTIVES: To evaluate changes in the number of CT scans in emergency department (ED) patients during and after the COVID-19 pandemic and the associated radiation exposure. MATERIALS AND METHODS: This single-center retrospective study at a tertiary university medical center included all ED patients from 2018 to 2023, divided into three phases: pre-pandemic (01/2018-02/2020), pandemic (03/2020-12/2022), and post-pandemic (01/2023-12/2023). Radiation exposure was assessed via effective dose. One CT scanner was replaced and stroke protocols were optimized in 06/2021. Kruskal-Wallis/Post-hoc Dunn tests were used. RESULTS: Overall, n = 374,697 ED patients (mean age, 53 years ± 22 [SD], 196,543 men) and n = 122,161 ED CT scans were included. In the pandemic and post-pandemic phase the number of CT scans per 100 ED patients showed a significant increase compared to the pre-pandemic phase (n = 31.4 [pre] vs 33.4 [pandemic] vs 33.0 [post], p1,3 < 0.01), particularly for pulmonary embolism (PE, +65%) and stroke protocols (+24%) in the pre-post-comparison. The mean effective dose per CT scan (E [mSv] = 3.85 vs 4.63 vs 4.70) and per ED patient (E [mSv] = 1.22 vs 1.56 vs 1.55) were significantly elevated (p1,3 < 0.01), whereas the mean effective dose per PE and stroke CT scan decreased by 7% and 48%, respectively. CONCLUSION: CT utilization increased significantly during the pandemic and remained elevated thereafter, independently of the technical changes. Effective dose per CT scan and per ED patient increased in the pre-post-comparison despite decreasing effective dose per PE and stroke CT scan.