Estimation of fetal dose in abdominal radiography using pregnant female phantom Tena: Monte Carlo computational study

Careful management of pregnant patients undergoing diagnostic and interventional procedures due to fetuses’ high sensitivity to ionizing radiation is of special interest. Accurate fetal dosimetry is important for risk-benefit analysis ensuring protection of both mother and unborn child. This study aims to assess the suitability of Tena pregnant female phantom for fetal dosimetry in diagnostic and interventional radiology (DIR) beams. Five different teams, using two different codes, participated in the first part of Monte Carlo (MC) simulations to validate simulation of radiography beam against measurements in simple geometry. Then, Tena tissue substitute materials were tested by benchmarking the MC simulations against ICRP and ICRU tissue materials in the same geometry. Additionally, the abdominal radiography procedure on the Tena physical phantom was simulated according to the DICOM data from the procedure. Then MC-calculated fetal doses were compared among participants and with fetal dose measured in a previous study for this procedure. MC simulations of simple geometry in Tena soft tissue substitute material complied well with ICRU and ICRP soft tissue substitute materials. The MC-calculated average fetal dose for the abdominal radiography procedure was (0.55±0.04) mGy, with heterogeneous dose distribution within the fetus (ranging from 0.41 mGy to 0.9 mGy). This result complied with measurements. Tena substitute materials are suitable for fetal dosimetry in DIR radiology beams. Comparison of measured and calculated fetal dose in radiography beam showed that special attention should be given to the position of detectors (experimental and MC simulation) since the dose distribution within the fetus is heterogeneous.