ORIGINAL INVESTIGATION Projected Cancer Risks From Computed Tomographic Scans Performed in the United States in 2007

scans in the United States (US) has increased more than 3-fold since 1993 to approximately 70 million scans an-nually. Despite the great medical benefits, there is con-cern about the potential radiation-related cancer risk.We conducted detailed estimates of the future cancer risks from current CT scan use in the US according to age, sex, and scan type. Methods: Risk models based on the National Research Council’s “Biological Effects of Ionizing Radiation ” re-port and organ-specific radiation doses derived from a national survey were used to estimate age-specific can-cer risks for each scan type. These models were com-bined with age- and sex-specific scan frequencies for the US in 2007 obtained from survey and insurance claims data. We estimated the mean number of radiation