Avaliação dosimétrica em Unidades de Terapia Intensiva Neonatais com a inserção de blindagem entre as incubadoras utilizando o Método Monte Carlo

Abstract

During hospitalization in the Neonatal Intensive Care Unit (NICU), neonates undergo imaging exams to diagnose or monitor the progress of diseases. The number of exposures can vary considerably based on the severity of the patient's condition and the duration of their hospital stay. The frequency of imaging exams during hospitalization has become a frequent concern in the hospital setting, as younger patients are more sensitive to ionizing radiation than adult patients due to higher mitotic activity. This study aimed to quantify and analyze the radiation doses in neonates exposed to the radiation beam during chest exams with mobile X-ray equipment in the NICU. Additionally, the study sought to evaluate the doses received by newborns in incubators adjacent to the examined neonates, considering the insertion of shields of different materials and thicknesses between the incubators. The study was conducted computationally using the Monte Carlo N-Particle Transport (MCNP) code, version 6.2, and virtual anthropomorphic phantoms representing the analyzed neonates. The highest reduction in doses to the neighboring neonate was observed when a thicker shield, specifically 0.5 mm, was used. Among the materials evaluated as shielding, an effective dose reduction for the neighboring neonate was approximately 99.6% for lead, 99.5% for bismuth, and 98.9% for a combination of bismuth and barium. These results demonstrated that the use of shielding between incubators in the NICU can significantly reduce the radiation doses to which the neighboring neonate is exposed, thereby avoiding unnecessary exposure to ionizing radiation.