Many tools and strategies exist to enable the reduction of radiation exposure from computed tomography (CT). The common CT metrics of x-ray output, CTDI_vol and DLP, are explained and serve as the basis for monitoring radiation exposure from CT scans. Many strategies to dose optimize CT protocols are explored that, in combination with available hardware and software tools, allow robust diagnostic quality CT scans to be performed with a radiation exposure appropriate for the clinical scenario and the size of the patients. Specific emergency department example protocols are used to demonstrate these techniques.