Report from NCRP: U.S. physicians remain oblivious to radiation exposure risks

April 18, 2007

Radiologists, referring physicians, and the U.S. public all need more education on the benefits and risks of medical imaging devices using ionizing radiation.

Radiologists, referring physicians, and the U.S. public all need more education on the benefits and risks of medical imaging devices using ionizing radiation.

That was the message of Dr. James A. Brink's keynote address Monday at the 43rd National Council on Radiation Protection and Measurements meeting.

Brink, chair of diagnostic radiology at Yale University School of Medicine, highlighted remarks from a study presented Monday morning by Dr. Fred A. Mettler Jr. Preliminary findings from Mettler's study indicate that radiation exposure from medical imaging has risen by a factor of five since the 1980s, primarily due to the greatly increased use of CT and nuclear cardiology procedures.

Brink expressed frustration with physicians who place their own egos ahead of their patients' needs in determining when imaging involving exposure to ionizing radiation is performed.

"We need to make sure that we are all on the same page about the appropriate use of CT and the understanding of its risks and benefits," he said.

Brink presented evidence that soaring radiation exposure from CT is becoming a global issue. He cited a study published last year that estimated the mean effective dose per capita in Luxemburg. Researchers found that between 1994 and 2002, the dose increased by about 25%. CT alone accounted for about 50% of that.

The study was done in response to a directive issued in 1997 by the European Union requiring member states to come up with regulations for appropriate exposures. Many regulations have already become law in countries such as the U.K., where strict criteria govern who may order tests involving ionizing radiation. Laws require physicians to be educated in the risks versus the benefits of such tests. Physicians must refuse to perform tests that are neither appropriate nor justified, Brink said.

"So what we are trying to bring along in the U.S. from a voluntary standpoint is actually dictated by law in Europe and many countries," he said.

U.S. physicians need to use CT only when other imaging tests won't suffice, avoid repetitive studies, tailor examinations to the patient and application, and try to reduce dose as much as possible. A recent survey showed that only 9% of referring physicians believed that there was an increased risk of cancer from CT, he said.

Brink proposed a set of suggestions, including physicians' education and tailoring of CT according to patients' age, gender, and body habitus. He listed several measures: use of gender-based dose reduction techniques such as breast shields in younger patients, utilization of automated dose exposure controls available with most scanners, use of low-dose protocols whenever possible, use of tube current modulation, particularly for cardiac CT, and dose monitoring.

He also proposed asking the American College of Radiology for more stringent CT accreditation requirements, as well as standardized dose metrics for adult and pediatric tests.

Special section: Exclusive coverage of the 2007 National Council on Radiation Protection and Measurements meeting

This year's historic NCRP meeting reveals the disturbing growth of patient exposure to ionizing radiation from medical imaging and proposes practical solutions to regulate its growth. Extended coverage from Diagnostic Imaging lays out the facts and recommendations to better protect patients, physicians, and medical staff.

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