Dr Redberg's editorial addressing President Obama's physical examination1 takes issue with the computed tomographic (CT) scan for coronary calcium he reportedly received, citing the potential associated cancer risk and the lack of proven benefit in low-risk persons.2 The implications of coronary artery disease screening with CT for health care cost are important, but the discussion of risks and benefits for President Obama deserves clarification. The projected cancer risk of 9 (range, 3-42) per 100 000 persons3 cited in this editorial is a point estimate, associated with considerable uncertainty, for a 40-year-old man, imparted by the median dose of a range of multidetector-row CT scan protocols. By contrast, President Obama is 48 years old and reportedly underwent electron-beam CT (EBCT).1,2 An older technology no longer manufactured or sold by the major CT vendors but still used in a number of institutions for calcium scoring, EBCT has a more standardized scan protocol that imparts a considerably lower radiation dose. Thus, the risk from such an EBCT scan would be approximately a third of that cited, without the potential for being much higher.
Einstein AJ. President Obama’s Coronary Calcium Scan. Arch Intern Med. 2010;170(13):1175–1176. doi:10.1001/archinternmed.2010.212