ACR Appropriateness Criteria®

Quality initiatives: CT radiation dose reduction: how to implement change without sacrificing diagnostic quality

The risks and benefits of using computed tomography (CT) as opposed to another imaging modality to accomplish a particular clinical goal should be weighed carefully. To accurately assess radiation risks and keep radiation doses as low as reasonably achievable, radiologists must be knowledgeable about the doses delivered during various types of CT studies performed at their institutions. The authors of this article propose a process improvement approach that includes the estimation of effective radiation dose levels, formulation of dose reduction goals, modification of acquisition protocols, assessment of effects on image quality, and implementation of changes necessary to ensure quality. A first step toward developing informed radiation dose reduction goals is to become familiar with the radiation dose values and radiation-associated health risks reported in the literature. Next, to determine the baseline dose values for a CT study at a particular institution, dose data can be collected from the CT scanners, interpreted, tabulated, and graphed. CT protocols can be modified to reduce overall effective dose by using techniques such as automated exposure control and iterative reconstruction, as well as by decreasing the number of scanning phases, increasing the section thickness, and adjusting the peak voltage (kVp setting), tube current-time product (milliampere-seconds), and pitch. Last, PDSA (plan, do, study, act) cycles can be established to detect and minimize negative effects of dose reduction methods on image quality.