CAD Radiation Doses Vary Globally, Higher in Lower-Income Countries

Radiation doses during coronary artery disease (CAD) testing reveal significant global disparities, with patients in lower-income countries often exposed to higher levels of radiation than those in wealthier nations. A recent study published in JAMA highlights these variations, underscoring the need for standardized protocols, updated equipment, and improved training to ensure patient safety worldwide.

Regional Disparities in Radiation Exposure

The INCAPS 4 study, a comprehensive global evaluation of cardiac imaging centers, analyzed data from over 19,300 patients across 101 countries. Researchers found that more than 20% of patients undergoing nuclear cardiology tests and over 40% of those receiving CT angiography exceeded guideline-recommended safety thresholds for radiation exposure. The study, led by Andrew J. Einstein, MD, PhD, at NewYork-Presbyterian Hospital/Columbia University Irving Medical Center, revealed a clear correlation between a country’s income level and the average radiation dose administered during these procedures.

Specifically, the average radiation dose for nuclear cardiology was 20% higher in low- and middle-income countries compared to high-income nations. For coronary CT angiography (CTA), the disparity was even more pronounced, with doses up to 96% higher in low- and lower-middle-income countries. The lowest average doses were recorded in Western Europe, while the highest were observed in Latin America (for nuclear cardiology) and Africa (for CTA). These findings suggest that access to modern technology, adherence to established safety protocols, and adequate training play a crucial role in minimizing radiation exposure during CAD testing.

Understanding the Risks of Radiation Exposure

Coronary artery disease testing, while essential for diagnosis and treatment planning, involves exposure to ionizing radiation. While the benefits of accurate diagnosis generally outweigh the risks, it’s important to understand the potential long-term consequences of radiation exposure. Ionizing radiation can damage DNA, increasing the risk of developing cancer over time. The risk is cumulative, meaning it increases with each exposure. The Food and Drug Administration (FDA) provides resources on radiation safety in medical imaging, emphasizing the importance of minimizing exposure whenever possible.

The study evaluated procedures against a target of 9 mSv (millisieverts) or less, as recommended in guidelines published in the Journal of Nuclear Cardiology. While a single diagnostic imaging procedure typically delivers a relatively low dose of radiation, the cumulative effect of multiple tests over a lifetime can be significant. It’s important to note that the risk of cancer from a single imaging test is slight, but it’s not zero.

Factors Contributing to Dose Variation

Several factors contribute to the observed variations in radiation dose. These include the type of scanner used, the specific radiopharmaceutical employed in nuclear cardiology, and the implementation of individual equipment features, and protocols. Adherence to guideline-derived best practices is also critical. For example, newer CT scanners often incorporate dose-reduction technologies, and optimized imaging protocols can minimize radiation exposure without compromising image quality. Recent advancements in shielding technology are also showing promise in reducing radiation exposure during certain procedures.

The researchers emphasize that limited attention has been paid to ensuring the implementation of safety standards as these technologies have become more widely available globally. As the incidence of CAD continues to rise in many parts of the world, the demand for diagnostic imaging is also increasing, potentially leading to a greater number of radiation-attributable cancers if safety measures are not prioritized.

Implications for Global Health

The findings of the INCAPS 4 study have significant implications for global health policy and practice. The study underscores the need for international collaboration to promote the adoption of standardized protocols and best practices for cardiac imaging. This includes providing training and resources to healthcare professionals in low- and middle-income countries, as well as investing in modern imaging equipment.

the study highlights the importance of ongoing monitoring and surveillance of radiation doses in cardiac imaging centers. Regular audits and quality control measures can help identify areas for improvement and ensure that patients are receiving the lowest possible radiation dose consistent with diagnostic accuracy. The researchers suggest that future research should focus on evaluating the effects of various factors on radiation dose and developing strategies to reduce exposure, particularly in resource-constrained settings.

What’s Next: Closing the Gap in Cardiac Imaging Safety

Addressing the disparities in radiation exposure during CAD testing requires a multi-faceted approach. Implementation science validation and comparison of different approaches are needed to close gaps in care and ensure quality CAD imaging worldwide. This includes developing and testing strategies to reduce radiation dose, particularly in low- and middle-income countries. The researchers call for continued efforts to build capacity, improve training, and promote the adoption of best practices to ensure that all patients have access to safe and effective cardiac imaging.

Ongoing surveillance and data collection will be crucial to track progress and identify emerging challenges. Collaboration between international organizations, healthcare providers, and equipment manufacturers will be essential to achieve meaningful improvements in patient safety and reduce the risk of radiation-attributable cancers.