Patient Exposure from Radiologic and Nuclear Medicine Procedures in the United States and Worldwide: 2009-2018.

The U.S. National Council on Radiation Protection and Measurements (NCRP) conducted a retrospective assessment of the U.S. data, and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) performed a similar worldwide assessment for 2009-2018 (with most data from 2014 to 2017). Using the data from those reports, the frequency of radiologic and nuclear medicine studies, annual collective, and per capita effective dose in the United States for 2016 were compared with worldwide estimates from 2009 to 2018. There were an estimated 691 million radiologic, CT, dental, and nuclear medicine studies performed in the United States in 2016, which represented 16.5% of the 4.2 billion performed worldwide. The United States also accounted for 74 million CT procedures (18% of the world's estimated total), 275 million conventional radiology procedures (11% of the world's total), 8.1 million interventional radiologic procedures (34% of the world's total), 320 million dental radiography procedures (29% of the world's total), and 13.5 million nuclear medicine procedures (34% of the world's total). The U.S. collective effective dose was 717 000 person-sieverts (17.6% of the world's total). The average annual individual effective dose in the United States was 2.2 mSv compared with 0.56 mSv worldwide. The United States accounts for a large and disproportionate share of global medical radiation procedures and collective effective dose, but use of CT has increased more in other countries compared with the United States.