JAMA study shows wide global variation in cardiac imaging radiation dose

A study published February 25 in JAMA has reported dramatic variations in radiation exposure from coronary artery disease (CAD) imaging across 101 countries, highlighting the need to improve imaging safety worldwide.

The research found that “radiation doses varied significantly between imaging tests and among patients receiving the same tests across centers, regions, and country income strata,” according to a team led by Andrew Einstein, MD, PhD, of Columbia University Irving Medical Center/NewYork-Presbyterian Hospital in New York City.

“[Our] findings have far-reaching implications,” the group noted. “The data can inform national and regional policies aimed at standardizing imaging practices, particularly in [low- and middle-income countries] where doses are typically higher and regulatory frameworks may be less robust.”

Cardiac imaging plays an essential role in diagnosing CAD, underscoring the importance of ensuring that patients have access to safe, standardized, and optimized imaging care, the investigators explained. To assess the dose ranges for cardiac imaging exams around the world, they conducted an analysis that included data from 19,302 patients from 101 countries who underwent nuclear cardiology, coronary CT angiography (CCTA), or calcium scoring (CACS) during one week in 2023.

The group reported that CCTA showed the highest radiation doses as well as the largest disparities, with a global median dose of 7.4 mSv, for example, a median dose of 4.6 mSv in Western Europe, and a median dose in Africa of 25.2 mSv. The team also observed radiation dose variability in nuclear cardiology exams such as SPECT or PET, though PET generally produced lower doses (median, 2 mSv). Western Europe posted the lowest median exposures for nuclear cardiology exams overall, at 4.8 mSv, while Latin America showed the highest median dose (7.8 mSv).

What contributed to the discrepancies? A country’s income level, the authors wrote, noting that patients in low- and lower‑middle–income countries received 20% higher doses for nuclear cardiology and up to 96% higher doses for CCTA, compared with those in high‑income countries. In part, this phenomenon was due to the use of older imaging technology (the median dose for CCTA with newer technology was 6.2 mSv vs. a dose of 14 mSv for exams performed using older technology). But technology wasn’t the only factor contributing to higher radiation dose: The study found that “a larger percentage of the variance was explained by clustering of practice patterns at the center and country levels.”

The study results carry major implications as CAD rates rise around the world, according to the investigators, who warned that “these findings … identify a critical need for training, standardized protocols, and updated equipment to reduce radiation worldwide” and highlighted that “a multifaceted, worldwide effort is needed to reduce these marked variations.”

Access the full study here.