Ionizing radiation

Advanced diagnostic imaging has been a transformative technology in medicine. In particular, computed tomography (CT) has allowed us to look inside the body in ways previously unimaginable, to rapidly make and exclude diagnoses, to direct treatment, and to potentially prevent unnecessary admissions and procedures. The benefits of a CT with an appropriate indication far outweigh the risks of radiation from CT. Perhaps because the risks of CT are relatively low, these risks remained largely unexplored until recently and now have garnered increasing scrutiny. With the dramatically increasing volume of studies performed over the past two decades, providers began observing multiply and repeatedly imaged patients accruing high levels of cumulative radiation and raising concerns about the attendant risks. Cumulative exposure due to ionizing radiation now surpasses the levels of exposure acquired as part of the natural "background" radiation in the USA (Ionizing Radiation Exposure of the Population of the United States, Report No. 160. Bethesda, MD: National Council on Radiation Protection & Measurements; 2009). Ionizing radiation can have dangerous effects on the body and at high levels can be lethal. Multiple organizations including the US Department of Health and Human Services have classified ionizing radiation as a carcinogen. Recognition of this potential overuse has led to increased awareness and efforts to optimize imaging. Overall, there has been an accompanying plateau in the rate of imaging in the USA. However, there is still much work to do to optimize our use of imaging.