Chest CT Use Remains Elevated Post-COVID, Study Finds, as Radiation Doses Decline

A new multicenter study published in European Radiology charts how use of chest CT imaging shifted before, during, and after the COVID‑19 pandemic—and suggests that some of those changes have become the new normal. 

Researchers collected data from 10 public hospitals in Switzerland, analyzing more than 241,000 CT scans between January 2019 and December 2024 using a commercial dose management system. Of these, nearly 63,000 were chest CT exams, accounting for about 26 % of total CT utilization. 

The study documents a sharp rise in chest CTs during the pandemic period (March 2020–April 2023), followed by a stabilization or plateau in the post‑pandemic phase (May 2023–December 2024). The overall number of all CT exams also rose steadily over the entire period, with the normalized (per device) average chest CT count climbing from about 636 per year pre‑pandemic to over 1,058 by 2024. 

Importantly, the average radiation dose per patient (as measured by CTDIvol and other metrics) did not increase alongside scan volume; in fact, dose exposure for chest CTs declined modestly over time. This suggests that improvements in CT hardware and protocol optimization have helped contain radiation risk even in the face of higher usage. 

The authors also observed shifts in scanning protocols over the course of the study. Before the pandemic, combinations such as thorax‑abdomen scans comprised a significant share of chest exams; during COVID‑19, pulmonary embolism protocols gained relative prominence, while in the post‑pandemic phase, native thorax protocols increased their share again, and pulmonary embolism scans fell in proportion. Scan lengths also increased overall, particularly for thorax‑abdomen protocols, reflecting broader imaging indications during and after the pandemic. =

The authors interpret their findings as evidence that the pandemic influenced sustained changes in imaging practice: even though the acute surge in demand subsided, CT usage did not revert to pre‑pandemic levels, and many centers have retained the dose management and protocol strategies developed during the crisis. 

They note some limitations: their data are drawn from imaging log systems rather than detailed clinical records, so the study cannot definitively attribute causes for dose changes or map long‑term health impacts of cumulative exposure. The authors suggest further work is needed to refine dose optimization and assess outcomes associated with increased CT utilization.