Radiology: U.S. collective radiation dose doubles
The total collective radiation dose to the U.S. population has doubled since 1980 and U.S. per-capita annual effective dose from medical procedures was six times greater in 2006 than it was in 1980, according to an article published in the November issue of Radiology.

According to Fred A. Mettler, Jr., MD, and colleagues from the radiology and nuclear medicine services at the New Mexico VA Health Care System in Albuquerque, the U.S. accounted for about 377 million diagnostic and interventional radiologic exams and 18 million nuclear medicine exams in 2006 – 12 percent of radiologic procedures and 50 percent of the nuclear medicine procedures performed globally.

The authors examined global data on radiation sourcesbetween 2000 and 2007 that were collected and analyzed by the United Nations Scientific Committee on the Effects of Atomic Radiation as well as frequency and dose information collected and analyzed by the medical subgroup of the Scientific Committee 6-2 of the National Council on Radiation Protection and Measurements.

According to the authors, since 1950, the estimated number of radiologic and nuclear medicine procedures increased 15-fold. CT scanning accounts for almost 50 percent of the collective effective dose from medical procedures in the U.S., although it accounted for only 17 percent of the procedures. The number of CT scans has increased by more than 10 percent per year over the last 15 years. Chest radiography accounts for 50 percent of all exams and exams of extremities account for another 20 percent, but together it accounts for only 14 percent of collective effective dose.

Cardiac catheterization procedures increased from 2.45 million in 1993 to 3.41 million in 1997 and to 4.6 million in 2006, the authors reported. These techniques now account for about 28 percent of the procedures and 53 percent of the collective effective dose from interventional procedures. Cardiac procedures account for almost 60 percent of the total number of nuclear medicine procedures and more than 85 percent of the collective effective dose.

The total collective effective dose to the U.S. population from all radiation sources has doubled since 1980, according to the authors, predominantly due to the large increase in medical exposures. The frequency of diagnostic radiological exams increased by a factor of 10 between 1950 and 2006, while the per-capita annual effective dose from medical procedures increased by six-fold from about 0.5 mSv in 1980 to 3.0 mSv in 2006.

Global estimates for the period between 2000 and 2007 suggest that about 3.6 billion medical procedures with ionizing radiation were performed annually, including 3.1 billion diagnostic radiologic, 500 million dental and 37 million nuclear medicine exams. The average per capita effective dose worldwide has approximately doubled over the past 10-15 years.