Referring physicians unsure of CT radiation risks
Ordering physicians have limited knowledge of CT-related radiation exposure and its associated risks, according to a study presented this week in Boston at the 2009 annual meeting of the American Roentgen Ray Society (ARRS).

The researchers collected more than 100 surveys completed by physicians from various specialties who order CT scans at a tertiary-care teaching hospital.

"When physician knowledge regarding radiation was assessed, 63 percent underestimated the radiation dose of one abdominal-pelvic CT in chest radiograph equivalents," said the study's lead author Jeremy McBride, MD, from the Carilion Clinic in Roanoke, Va. "When asked if they believed a single abdominal-pelvic CT increases a patients' risk of cancer nearly 80 percent responded affirmatively; however, 74 percent significantly underestimated the risk as published in literature."

"When asked if they regularly disclose the risks associated with CT scans with patients, nearly 60 percent responded affirmatively; however only 20 percent said the risk of exposure was part of that disclosure," McBride said.

"When asked if radiation exposure and cumulative prior radiation exposure influenced their decision, 48 percent and 59 percent respectively, responded it had no or little influence on their decision. Forty-seven percent reported that risk of litigation significantly influenced their decision to order a CT scan on a given patient," he said.

"Most of the time, when a CT scan is ordered it can be justified. When a CT is appropriately ordered patients should be aware that the examination has been recommended based upon its diagnostic value and that radiation exposure will be minimized," McBride said. "If patients are concerned, they should feel comfortable asking their physician how an imaging examination will answer a specific question and how it will affect their clinical management. They can also make their physician aware of their concern about radiation exposure from medical imaging and discuss appropriate alternatives."

McBride concluded that radiation education "should be discussed with medical students and residents during training, as well as with practicing physicians in the form of institutional conferences or workshops. Radiologists and scientists trained in the field of radiation protection in medicine should be contacted by ordering physicians for consultation prior to ordering whenever there are questions regarding the right test or the safety of the test for a particular patient."

Ben E. Paxton, MD, and Richard M. Wardrop III, MD, also from Carilion, worked with McBride on the study.