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Big dose of x-ray after heart attack

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“These findings reinforce that better tracking systems are needed to quantify the radiation dose a given patient is accumulating throughout the diagnostic process and to help clinicians weigh the risks and benefits of future imaging,” Prashant Kaul says. While several billion imaging studies are performed worldwide each year, at least one-third are cardiovascular procedures.

DUKE (US)—Acute heart attack patients receive an average dose of radiation that is equal to 725 chest X-rays, or 30 percent of the recommended annual limit, during an average hospital admission, according to a new study.

Lifetime exposure to large doses of ionizing radiation has been linked to the development of cancer.

“In the past, there has been a lot of attention focused on analyzing radiation exposure per scan but we asked a different question: What is a patient’s exposure per diagnosis?” says Prashant Kaul, a fellow in cardiovascular medicine at Duke University Medical Center and lead author of the study.

The study, presented at the American Heart Association’s Scientific Sessions 2009, is the first to analyze radiation exposure throughout the course of a hospital stay instead of an individual procedure.

“These findings reinforce that better tracking systems are needed to quantify the radiation dose a given patient is accumulating throughout the diagnostic process and to help clinicians weigh the risks and benefits of future imaging,” Kaul says. While several billion imaging studies are performed worldwide each year, at least one-third are cardiovascular procedures.

The research team analyzed the average cumulative radiation dose for patients hospitalized with an acute heart attack, tracking 64,074 patients (23,394 women and 40,680 men) who were hospitalized at 49 U.S. academic hospitals enrolled in the University HealthSystem Consortium.

Over three and a half years, a total of 276,651 procedures involving radiation were performed on these patients.

Researchers analyzed use of common diagnostic procedures involving ionizing radiation, such as chest X-rays, CT-scans, stress tests, diagnostic cardiac catheterization, and percutaneous coronary intervention.

On average, the cumulative radiation dose during a heart attack patient’s hospitalization was approximately 14.5 millisieverts (mSv), a measure of radiation dose to tissue. Radiation workers have an annual limit of 50 mSv.

The team cautions that more research is needed to understand why the amount of radiation patients receive varies.

“We are conducting an analysis to determine the underlying drivers, which may be patient-based, hospital-based, or individual practice patterns,” explains Manesh  Patel, study coauthor.

“In some cases, such as older patients with complex heart disease, extra testing may be necessary to make a diagnosis,” he adds. “However, we may also uncover opportunities to educate clinicians about safe and effective ways to utilize these procedures.”

The study was funded by the Duke Clinical Research Institute.

Duke University news: www.dukenews.duke.edu/

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