Radiation dose management: part 2, estimating fetal radiation risk from CT during pregnancy.

OBJECTIVE The purpose of this article is to review fetal radiation doses and associated risks resulting from CT performed during pregnancy. The scanning parameters that influence dose and the techniques for estimating and reducing dose are explained. CONCLUSION Fetal radiation doses for CT examinations in which the fetus is not directly imaged-for example, head or chest CT-are minimal and need not figure in the risk-benefit analysis to perform the examination. In contrast, radiation dose should be considered with abdominopelvic CT because the fetus is likely to be exposed directly to the scanning beam. Safe implementation of CT in this setting requires an understanding of the factors influencing radiation dose. With this knowledge, when a risk-benefit analysis in a given clinical situation favors imaging using CT, the radiologist need not withhold or delay the examination and can achieve diagnostic-quality images while reducing radiation exposure.