CT radiation doses have decreased substantially over the last decade
Adult CT radiation doses have decreased substantially over the last decade in the U.S., according to new research published Tuesday.
About 10 years have passed since data underlying the most recent national benchmarks for radiation dosing were collected. This underscores the need for updated reference values, as these guidelines may not reflect new advances in scanner technology, reconstruction methods and protocol changes, experts write in RSNA’s Radiology.
Researchers recently aimed to address this information gap, analyzing adult CT acquisitions performed across U.S. facilities in 2025. They discovered clear progress, with CT diagnostic reference levels declining an average of nearly 22% since 2014.
“The magnitude and consistency of these reductions across examination categories suggest that such advances have translated into measurable, population-level dose reductions in routine clinical imaging in the United States,” Kalpana M. Kanal, PhD, with the Department of Radiology at the University of Washington, Seattle, and colleagues wrote July 28.
The study utilized info from the Imalogix radiology optimization platform, targeting the 10 most common adult CT exam categories. Dosing data were extracted from structured reports and normalized at the acquisition level, with patients’ size quantified using various factors. The final sample included about 5.2 million CT exams acquired across almost 600 U.S. healthcare facilities.
Along with diagnostic reference levels, dose-length product—a key measure of patient dosing across the entire CT scan—also decreased by 20%. Dose reductions relative to 2014 were greatest for chest exams with contrast (31%) and without (27%). Kanal and colleagues also charted smaller reductions for head exams without contrast material (4%).
Although the analysis did not determine causes of these reductions, experts believe they are consistent with broad changes in CT technology and clinical practice. These include adoption of machine learning-based reconstruction techniques, refinements in tubes used for scanners, improved detector efficiency and increasing protocol optimization.
Kanal and co-authors believe their analysis offers others a scalable, near real-time framework for maintaining diagnostic reference levels and achievable doses in the future.
“The scale, consistency, and automation of this framework support population-level benchmarking for quality improvement and protocol optimization,” the authors concluded. “The framework is also well positioned for future incorporation of image-quality metrics, enabling benchmarks that jointly characterize dose and diagnostic performance, and is readily extensible to additional CT applications and subpopulations as clinical practice and technology continue to evolve.”
Read more, including potential study limitations, in the Radiological Society of North America’s flagship journal.
Marty Stempniak has covered healthcare since 2012, with his byline appearing in the American Hospital Association's member magazine, Modern Healthcare and McKnight's. Prior to that, he wrote about village government and local business for his hometown newspaper in Oak Park, Illinois. He won a Peter Lisagor and Gold EXCEL awards in 2017 for his coverage of the opioid epidemic.