Comparison of estimated and calculated fetal radiation dose for a pregnant woman who underwent computed tomography and conventional X-ray examinations based on a phantom study.

This study aimed to determine the mean fetal doses for patients who underwent computed tomography (CT) and/or conventional X-ray (CXR) examinations. In addition to developing an approach to estimate the fetal dose based on data registered in the picture archive and communication system (PACS), the radiation doses for pregnant women and their fetuses were estimated using the VirtualDoseCT and VirtualDoseIR softwares. To verify the data, the fetal dose was measured using thermoluminescent dosimeters (TLDs) implanted at different uterus sites of an anthropomorphic pregnant phantom. Calculated fetal dose values were estimated in relation to the dose-area product (DAP) and volume CT dose index (CTDIvol). DAP and CTDIvol were obtained from data registered in the PACS. The fetal doses varied between < 0.001 and 3.9 mGy and between 0.26 and 16.21 mGy for the CXR and CT examinations, respectively. These values were similar to those of previous studies on both imaging modalities. The conversion factors obtained to calculate fetal doses for CXR examinations were between 0.01 and 0.73 mGy/Gy cm2, whereas they varied between 0.02 and 0.61 mGy/mGy for CT examinations. Overall, the fetal dose conversion factors based on DAP and CTDIvol values can be used for fast fetal dose estimations in common CXR and CT examinations.