Estimative of conversion coefficients for absorbed and effective doses in pediatric CT examinations in two different PET/CT scanners

Abstract

The use of computed tomography (CT) in pediatric patients has grown substantially in recent years. As a result, there is an increase to maintain the radiation doses as low as possible, in order to avoid long-term effects, as cancer. In this work, the radiation doses on radiosensitive organs of pediatric patients undergoing head, chest and abdomen CT examinations, utilizing Monte Carlo simulations, were evaluated. In this sense, a new set of pediatric virtual anthropomorphic phantoms with Monte Carlo simulation was employed to determine the conversion coefficients for absorbed and effective doses. Two CT equipment were simulated, taking into account the main characteristics of those commercially available. The F6 tally (MeV/g) was employed to compute the absorbed organ doses. The obtained results were converted to conversion coefficients for all radiosensitive organs, considering all applied beams. The highest conversion coefficients for effective dose were for the newborn virtual anthropomorphic phantom. Therefore, this work provides a useful tool regarding the risks involving ionizing radiation in pediatric patients, employing a reliable technique.