It is imperative that responsible clinicians understand the relationship between computed tomography imaging and radiation-induced malignancy risk. As the concept of computed tomography-induced malignancy risk becomes more widespread, it is important that clinicians are well informed and are able to intelligently answer questions and concerns posed by their patients and are able to understand and discuss the issues with their radiologist colleagues. The purpose of this article is to review the history of ionizing radiation exposure growth in diagnostic imaging, to understand the biologic effects of radiation exposure, to define the growth of ionizing radiation from computed tomography in the United States, and to explore available mechanisms that can be used to control excessive patient radiation exposure.