WASHINGTON, Dec. 28 (UPI) -- Myocardial perfusion imaging, or nuclear stress tests, are considered essential for the diagnosis and management of coronary artery disease, but radiation levels during the tests are higher in the United States, according to a new study.
Researchers involved with the study, published by JAMA Internal Medicine, found patients in the United States are exposed to more radiation during the scans than those in other countries.
Coronary artery disease, the most common type of heart disease in the United States, is caused by the buildup of cholesterol and other substances, which affects the proper flow of blood to the heart. Myocardial perfusion imaging uses radioactive material and physical activity to allow doctors to measure heart function relatively noninvasively.
While the test is considered essential to managing the condition, and millions are performed each year, researchers said the exposure to ionizing radiation raises concern about potential radiation-related health effects.
The researchers used data collected as part of the IAEA Nuclear Cardiology Protocols Study from 308 nuclear laboratories in 65 countries, 50 of which were located in 22 U.S. states. Data was collected between March and April 2013 on 7,911 patients, of whom 1,902 were Americans.
The data showed a patient in the United States is exposed to about 20 percent more radiation on average than patients in the other countries in the study. Less than a quarter, 24 percent, received radiation doses lower than the recommended 9 millisieverts. People treated outside the United States received 9 mSv about 43 percent of the time. Outside the United States, doses of radiation were below 9.7 mSv about half the time, while the dose was 11.6 mSv about half the time.
In an editorial published in JAMA Internal Medicine with the study, researchers suggest more careful use of the tests could reduce unnecessary exposure to radiation, however they also point out at least one method that could reduce radiation.
"Adopting a practice of stress-first imaging among patients undergoing MPI in the United States could result in a dramatic decrease in the average radiation dose without loss of clinical information," researchers in the editorial wrote, noting variation in dose is not unheard of. "The variation in radiation dose in the performance of MPI is consistent with what data have previously been reported for CT scans."