A new study revisits the debate over CT radiation risk, finding a link between greater use of CT scanning in a country and the percentage of patients getting higher cumulative doses of radiation over time.
Managing medical radiation has been a priority for decades, but the issue gained new prominence in April with the publication of a controversial paper linking CT use to future cancers.
- Critics accused study authors of sensationalizing the radiation dose issue, but researchers pointed out that they used existing models for radiation dose and cancer risk.
Enter the new study, in which a team led by international radiation safety expert Madan Rehani, PhD, calculated the number of patients getting over 100 mSv of cumulative radiation dose over five years across 27 countries, mostly in Europe.
- Radiation at such levels is concerning due to the established dose-response nature of current radiation theory – that is, higher doses are believed to lead to higher cancer risk.
Radiation dose exposure rates for CT, fluoroscopy-guided interventions, and PET were analyzed for 2022 for 513M people from Austria to the U.K., with a particular focus on patients getting over 100 mSv in a five-year period.
- For point of reference, a chest X-ray PA view is typically 0.02 mSv, a CT scan 1-10 mSv, and the average for a year of background radiation is about 3 mSv.
Researchers found …
- In all, 0.27% of the population received cumulative radiation exposure over 100 mSv.
- The countries with the highest rates of patients per 1k getting over 100 mSv included Belgium (4.52), Portugal (4.48), Luxembourg (4.19), and France (4.15).
- These same countries also tended to have the highest use rates of CT exams per 1k population, led by Portugal (285), Luxembourg (249), Belgium (226), and France (224).
- Countries with the lowest exposure rates over 100 mSv included Finland (1.09), Romania (1.1), Norway (1.64), and Bulgaria (1.76), and all had CT use rates below 100 exams per 1k population.
While the U.S. was not included in the study, other research shows it might fall at the upper end of the scale – if not at the top.
The Takeaway
The new study offers a sobering take on the radiation dose issue. While reasonable people can debate the exact link between low-level radiation exposure and cancer risk, it’s harder to justify such wide variation in CT use and cumulative radiation exposure between countries, especially those at similar levels of economic development.
