Calculation of Fetal Dose Pregnant women were referred to the Department of Medical Physics to determine the fetal radiation dose. Fetal radiation exposure was calculated by an expert physicist in this department. All of the pregnant women who were referred to the department were asked for documents that contained detailed information about the medical examination type, details of the procedure, and exposure parameters. To calculate the fetal dose, specific values for the following parameters were obtained for the medical examinations that were performed: 1) projection view (anteroposterior, posteroanterior, lateral, oblique) for each exposure; 2) imaging modality; 3) size of the X-ray field and image receptor plane or skin surface; 4) beam quality (peak tube potential, generator type and filtration); and 5) source-to-image receptor distance. Gestational age used in calculating the fetal dose was obtained using prenatal ultrasound data. We used the FetDose V4 software to calculate fetal doses from the radiographic and CT examinations. FetDose is a widely used software program that was developed for estimating fetal radiation doses (8-10). The fetal absorbed dose from a series of radiographic examinations (Df) when the quantity supplied was the entrance surface dose for each radiograph was calculated using the formula