Assessment of radiation doses in computed tomography scans using simulation models versus experimental verification and cancer risk estimation in pediatric phantom

Abstract Objective This study aims to develop a methodology for estimating the absorbed dose in various organs of a pediatric phantom during computed tomography (CT) scans. The approach combines Monte Carlo simulations with experimental validation to ensure the accuracy of the numerical results. Methods This study employed thermoluminescent dosimeters (TLDs) and GEANT4/GATE-based Monte Carlo simulations to estimate and validate organ dose measurements in a pediatric phantom. The phantom was irradiated utilizing a Siemens CT scanner at appropriate parameters (120 kVp and 60 mA). We calculated the dose at identical positions within the phantom using Monte Carlo simulations and subsequently compared the dose results. Results The absorbed doses recorded by the TLDs for the left eye, right eye, thyroid, left lung, right lung, left pelvic, right pelvic, and testes were 18.93 ± 1.02, 16.47 ± 0.86, 28.37 ± 1.63, 16.30 ± 1.06, 15.21 ± 1.26, 14.33 ± 0.01, 14.10 ± 1.6, and 17.91 ± 0.16 mGy, respectively. The calculated absorbed doses in the respective organs using GEANT4/GATE were: 16.96 ± 1.99, 16.75 ± 1.45, 29.61 ± 0.77, 16.92 ± 0.08, 16.26 ± 0.39, 15.07 ± 0.01, 14.91 ± 0.75, and 17.94 ± 0.041 mGy. The results indicate a strong concordance between the two methods, with percentage differences of 11.6%, 1.7%, 4.4%, 3.77%, 6.9%, 5.14%, 5.74%, and 0.17%, respectively. Conclusion The strong agreement between simulation results and experimental measurements enhances the ability to estimate absorbed doses in radiosensitive organs during CT scans. Additionally, the study utilizes phantom dose data to evaluate the risk of secondary cancers in susceptible organs, highlighting a relationship between lifetime risk and excess absolute risk for both males and females.