The Reading Room Podcast: Emerging Research and Current Perspectives on CT Radiation Dosing, Part 2

For future research on optimizing radiation dosing for computed tomography (CT) exams, Kalpana Kanal, PhD, would like to see more studies focus on indication-based diagnostic reference levels (DRLs). In a recent Reading Room podcast, Dr. Kanal pointed out that indication-based DRLs are commonly utilized in Europe but not as much in the United States.

“I think we need to start moving towards indication-based data because it depends on your clinical indication how much dose you need. … Is it a subtle diagnosis you're looking for or is it something very obvious that will impact how much dose you're using. That will give you different DRL values,” posited Dr. Kanal, a professor of radiology at the University of Washington in Seattle.

Emphasizing the need to monitor DRLs on a regular basis, Dr. Kanal and Mahadevappa Mahesh, MS, PhD, FAAPM, FACR, said their recent publication in Radiology — demonstrating an overall 21.8 percent decrease in DRLs for CT exams in adults — was based on 2025 data and published in a relatively short six-month timeframe. In contrast, a similar 2017 study coauthored by Dr. Kanal was based on 2014 data.

“We are trying to template (this so) DRLs can be published on a short period of basis within a year (or) within six months. That is the idea because DRL is not a one-time done deal. It has to be looked at over a period of time so you can correct yourself, not with the aim of going down, but to see what's being practiced and how (it) can be tightened up,” explained Dr. Mahesh, a professor of radiology and cardiology at the Johns Hopkins University School of Medicine.

Dr. Mahesh noted in the podcast that he is currently working on a cardiac CT DRL study that he plans to speak about at the upcoming RSNA conference next month. Dr. Kanal is working on a forthcoming study examining CT DRLs for pediatric patients.

For more insights from Dr. Kanal and Dr. Mahesh, listen below or subscribe on your favorite podcast platform.

(Editor’s note: This podcast was derived from a previous video interview published at the following link: https://www.diagnosticimaging.com/view/ct-radiation-dosing-where-things-stand-part-2 .)