CT Radiation Dose Reduction With Preserved Diagnostic Performance: How Far Have We Come Over 25 Years?
Dose reduction in CT imaging has been a topic of considerable interest for the last 25 years. Many new technologies have been introduced into commercial systems that individually can reduce doses by approximately 10-40% each, depending on the diagnostic task and starting dose level. Over time, these technologies have not only reduced radiation doses but have allowed improvements in image quality that otherwise would have raised doses.
In a recent paper in the American Journal of Roentgenology, authors Cynthia McCollough, PhD and Lifeng Yu, PhD review just how far we have come in dose reduction in the last 25 years. The authors provide examples of routine CT images of the head and abdomen from 1997 and compare both the dose and image quality to images from exams performed in 2025. They find that if physicians were willing to have the 1997 level of image quality, we would have seen a factor of 10 reduction in dose from the accumulation of these dose reduction technologies! The clinical standard of care in modern CT is of course much better image quality, but even then, there is a reduction in dose by a factor of approximately 2. The authors additionally focus on the importance of maintaining diagnostic performance and suggest that adoption of new image quality assessment methods is needed for non-linear reconstruction techniques, such as in iterative reconstruction or deep learning reconstruction techniques.