The manner in which radiation exposure occurs, whether acute or chronic, high or low dose, affects risk. Therapeutic radiation—administered at high doses to targeted areas of the body for limited amounts of time—differs from the intermittent exposure associated with diagnostic studies. Radiation exposure of atomic bomb survivors was acute, whereas exposure experienced by nuclear workers is chronic, low dose, and, in some ways, similar to lung screening participants. Studies of disparate groups, such as those who undergo therapeutic radiation (ie, high doses over short periods), may not apply to screening programs in which the exposure is low dose over long periods of time. The one comparison group to which chronic radiation exposure in a lung cancer screening program can be contrasted is nuclear industry workers.6 These studies, however, include very few workers with radiation exposures > 100 mSv, levels easily reached in lung cancer screening programs, per NLST criteria.3,5,6 As a result, it is not possible to directly contrast the relative exposure scenarios of nuclear industry workers with lung cancer screening participants.