In 2006, the U.S. population was exposed to seven times more radiation from medical imaging exams than in 1980, according to a National Council on Radiation Protection and Measurement (NCRP) report.

The increase was primarily a result of the growth in the use of medical imaging procedures, explained Kenneth R. Kase, MD, senior vice president of NCRP and chairman of the scientific committee that produced the report. "The increase was due mostly to the higher utilization of CT and nuclear medicine. These two imaging modalities alone contributed 36 percent of the total radiation exposure and 75 percent of the medical radiation exposure of the U.S. population."

The number of CT scans and nuclear medicine procedures performed in the United States during 2006 was estimated to be 67 million and 18 million, respectively.

Although the major reason for increased imaging utilization and the associated rise in radiation exposure is the improved healthcare resulting from these non-invasive, accurate imaging tools, there are concerns about overutilization of these exams, according to the American College of Radiology (ACR).

At a recent international conference of the NCRP, David A. Schauer, its executive director, cited self-referral as a primary, preventable driver of this dramatic increase in radiation exposure. Non-radiologist providers often lack even basic radiation safety training and may not be aware of potential repercussions to patients of ordering and often administering high volumes of scans, he said.

The NCRP said that it is working with its partners such as the ACR, World Health Organization (WHO) and others to address radiation exposure resulting from the significant growth in medical imaging and to ensure that referrals for procedures such as CT and nuclear medicine are based on objective, medically relevant criteria.