(NaturalNews) Coronary artery disease (CAD) is the leading cause of death in the United States and many heart attacks occur in people who've had no previous symptoms or warning. So a noninvasive imaging technique known as cardiac computed tomography (CT) angiography (CCTA) that evaluates the anatomy of the coronary arteries quickly and can find calcified and non-calcified plaques that could lead to a heart attack sounds like a great idea -- especially when the test is so specific it has about a 90% accuracy rate.
In fact, the 64-slice (meaning it scans 64 images per rotation) CCTA is currently being used in an increasing number of patients who go to the emergency room with chest pains or who have had abnormal stress tests. And some doctors are advocating using it on seemingly healthy people to look for hidden heart disease, too.
However, a new study just published in the Journal of the American Medical Association
points out that CCTA may not be the super safe test it has been hyped to be. In fact, it could be exposing countless people to high levels of radiation. That means, while checking for possibly non-existent heart disease, it could be promoting the development of cancer. Moreover, the researchers said while there are methods to reduce the dose of radiation the test produces, they are rarely used.
Jorg Hausleiter, M.D., of the Deutsches Herzzentrum Munchen, Klinik an der Technischen Universitat Munchen in Munich, Germany, and his research team investigated the magnitude of patient radiation
exposure of CCTA in daily practice, factors contributing to this radiation dose and the use of well-known strategies that could reduce radiation dose. Their International Prospective Multicenter Study On Radiation Dose Estimates Of Cardiac CT Angiography In Daily Practice, known as PROTECTION I for short, involved 1,965 patients
undergoing CCTA between February and December 2007 at 21 university hospitals and 29 community hospitals. Radiation was measured as dose length product (DLP) which the scientists said in a media release is the best way to find out how much radiation a patient is exposed to by the entire CT scan process.
The results were startling: the researchers found that the CCTA tests exposed the patients in the study to an estimated radiation dose equivalent to 600 chest x-rays per each CCTA.
According to background information in the JAMA article, many doctors are apparently clueless about the magnitude of radiation exposure their patients are receiving during CCTA -- and they are also unaware of the factors that contribute to radiation dose and what strategies could lower this exposure.
"With the constantly increasing number of CCTA-capable scanners worldwide, the volume of CCTA scans performed is likely to show substantial further increase," the authors wrote in the JAMA report. They added that the clinical usefulness of CCTA for the assessment of coronary artery disease should be weighed against the potential risk of cancer
caused by the high radiation exposure from the test.
"As CCTA is being used more frequently worldwide for diagnosing coronary artery disease, all strategies for reducing radiation exposure will finally reduce the patient's lifetime cancer risks. Although the associated risk is small (estimated lifetime attributable risk of death from cancer after an abdominal CT scan is 0.02 percent) relative to the diagnostic information for most CT studies, this risk needs to be realized especially when repeated CT scans
are being performed," the scientists said in a media statement.
According the American Cancer Society, ionizing radiation is a scientifically proven cancer-causing agent in human beings -- and the odds that cancer will result from radiation exposure increases as the dose increases. Many years may go by between the radiation exposure and the appearance of the cancer, the ACS web site states.
For more information:http://jama.ama-assn.org/cgi/content/short/301/5/500http://www.clinicalcorrelations.org/?p=679http://www.cancer.org/docroot/PED/content/PED_1_3X_Radiation_Exposure...
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