Review of radiation issues for computed tomography.

Over the past three decades, computed tomography (CT) has proven to be central in imaging evaluation. Multidetector technology continues to drive practice patterns by combining fast scanning with high quality data sets. This has resulted in new applications as well as improved use in traditional applications. With this recognition has also come the realization that there are potential costs of CT. One major cost is the radiation dose. Therefore, in order to begin to assess benefits (which are relatively familiar to radiologists) versus costs (which are less familiar), the issues related to CT radiation need to be addressed. Familiarity with measures of CT radiation and the actual doses delivered by CT are important issues as they provide a basis for understanding the potential cancer risks from CT radiation. Moreover, these justify development of strategies to minimize radiation dose. Strategies include obtaining only necessary CT examinations and adjusting the examinations based on scan indication, region examined, and patient size. These strategies must also be combined with efforts by manufacturers in development and implementation of technology aimed at radiation dose management, as well as efforts in research, education, and CT standards and regulation. This article reviews the subject of radiation dose with multidetector CT technology, including measures of CT radiation, the dose that can result from CT examinations, the risks of this amount of radiation, and strategies for minimizing CT radiation dose.