Source: International Atomic Energy Agency (IAEA) –
Cardiac imaging technologies, such as nuclear cardiology and computed tomography, are essential tools for diagnosing coronary artery disease. (Photo: AdobeStock)
Differences in the amount of radiation patients receive from diagnostic tests for coronary artery disease (CAD) have been revealed in a major international study coordinated by the International Atomic Energy Agency (IAEA) and Columbia University in the United States. The study underscores an urgent need for improved training, standardized protocols and updated equipment — particularly in low- and middle-income countries, where data suggests radiation doses could be lowered without compromising test results.
CAD occurs when the arteries that supply blood to the heart become narrowed or blocked, typically due to plaque buildup in the artery walls, a process known as atherosclerosis. When the heart does not receive enough blood, it can lead to chest pain, heart attacks, abnormal heart rhythms or heart failure.
CAD remains the leading cause of death worldwide, and the use of modern imaging tests to detect CAD has increased steadily in recent decades. The study, Worldwide Radiation Dose in Coronary Artery Disease Diagnostic Imaging, published yesterday in JAMA, the Journal of the American Medical Association, analyzed data from more than 19 000 patients at 742 centres in 101 countries, making it the largest and most comprehensive global assessment of radiation exposure from non-invasive cardiac imaging. Each centre collected and contributed data from one of nine defined weeks in the fourth quarter of 2023.
Researchers examined radiation doses from widely used imaging techniques, including nuclear cardiology tests and computed tomography (CT) scans of the heart. While many centres were able to keep radiation exposure within recommended limits, the study found marked variation between countries, regions and income levels, with some patients receiving higher doses of radiation than others for the same test.
“Radiation from medical imaging saves lives every day by enabling accurate diagnosis and treatment, but it must always be optimized,” said Professor Andrew J Einstein, the study’s principal investigator and corresponding author. Einstein is Director of Nuclear Cardiology, Cardiac CT and Cardiac MRI at the Seymour, Paul and Gloria Milstein Division of Cardiology at Columbia University’s Vagelos College of Physicians and Surgeons in New York City.
Key findings
The study found that median radiation doses varied widely by imaging modality, income levels and geography. Optimized protocols and use of newer technology, which often deliver clearer images, were consistently associated with lower patient exposure.
Patients in low- and middle-income countries often received significantly higher doses, particularly for coronary CT angiography, a test that is increasingly used because of CT’s availability and technological improvements.
“This study shows that where a patient lives, the resources available to a health system and how those resources are used can strongly influence how much radiation they receive — even when undergoing the same test,” Einstein said. “These differences are not inevitable. In many cases, the technology and knowledge to reduce dose already exist. The challenge is ensuring that they are applied consistently and equitably across the world.”
The authors emphasize that reducing radiation doses does not mean reducing diagnostic quality.
The IAEA’s role
For more than six decades, the IAEA has worked with countries to strengthen the safe and effective use of medical imaging, especially where access to advanced health care is limited. The findings of this study will help guide future efforts to improve radiation safety, while expanding access to life-saving diagnostic tools.
“This research provides critical evidence that can inform national policies and international action,” said Diana Paez, Head of the Nuclear Medicine and Diagnostic Imaging Section at the IAEA. Paez was the senior investigator and co-lead of the study. “By identifying where radiation doses are highest and why, we can better target training, quality assurance programmes and technical support to help countries optimize cardiac imaging for their populations,” she added
The study also highlights the importance of investing in modern imaging equipment and ensuring that health professionals are trained to use dose-reduction techniques effectively.
“Access to diagnostic imaging is essential for tackling the growing global burden of heart disease,” said May Abdel-Wahab, Director of the IAEA Division of Human Health. “At the same time, patient safety must remain central. This study underscores the need for updated equipment, harmonized standards and improved training to expand access while reducing unnecessary radiation exposure. Building on these findings, the next step is to work with partners to provide relevant continuing medical education and long-term training.”
The study points to further opportunities for peer-to-peer knowledge sharing, development of regional and global dose reference levels, and closer collaboration between regulators, professional societies and industry.
“As the use of cardiac imaging continues to grow worldwide, ensuring that every patient benefits from the safest possible practices is both a medical and an ethical imperative,” Einstein said. “Patients deserve the highest standards of safety while undergoing testing that is critical to heart health.”
The study was funded and conducted under the IAEA coordinated research project, IAEA Noninvasive Cardiology Protocols Study (INCAPS4).