Fetal Organ Dose Assessment during Chest CT Examination Using Monte Carlo/Gate Simulation

A CT scan of a pregnant patient is often a source of distress for the patient and staff. In addition, patients are usually worried about the risk of unfavorable effects on the fetus from radiation. Therefore, assessing radiation dose and related risks to the fetus and pregnant patient is an important aspect of radiation protection. The aim of this study is to estimate the fetal organ and effective dose during a chest CT protocol for a pregnant patient. For this purpose, we model the SOMATOM EMOTION 16 CT (Siemens Medical Solutions, Erlangen, Germany) and the pregnant patient using GATE code. The CT scanner is modelled based on the data provided by the supplier, operating at 80, 110 and 130 kV and 0.5–1.5 for the pitch, regarding the patient, she is modelled with a voxelized pregnant phantom (KATJA, 29 yr old) at the 24th week. Fetal effective doses are estimated to be 0.8, 1.7 and 2.4 mSv for 80, 110 and 130 kV, respectively. When the energy is decreased from 130 to 80 kV, the dose to the fetal organs in the heart and lenses is reduced by 64.3 and 64.6%. Moreover, the fetus organ dose is reduced by 21.5, 19.2, 30.0 and 17.6% for crane, eyes, heart and brain for a pitch ranging from 0.5 to 1.5. Since the cumulative dose to the fetus does not exceed 100 mGy, the doses to the fetus are considered acceptable.