Avaliação computacional das doses médicas e ocupacionais durante diagnóstico de COVID-19 em pacientes pediátricos empregando tomografia computadorizada

Abstract

In December 2019, a new Coronavirus, called Sars-CoV-2, was detected in China. This new Coronavirus has a high power of transmission and contamination of people through droplets and / or contaminated surfaces and objects, which led the World Health Organization (WHO) to decree the Covid-19 pandemic in March 2020. In addition, the Covid-19 causes serious respiratory problems and lung inflammation, causing the death of more than 1.5 million people across the world so far. The number of computed tomography (CT) examinations has increased in recent months, as CT images of the chest are being used as a way of diagnosing and monitoring the extent of pulmonary involvement in Covid-19. During the performance of the CT examination, it is necessary that a nursing / radiology professional perform manual ventilation on the patient with breathing difficulties. Thus, this professional is subject to risks of contamination to the Coronavirus and exposed to ionizing radiation. Given this exposition, this study is aimed to determine occupational doses, in various situations, through Monte Carlo simulation together with simulator objects representing professionals and pediatric patients, during the CT scan of the chest. The effective dose conversion coefficient (𝐶𝐶(𝐸)) was obtained in two possible positions of the professional, and these were higher when the professional is positioned in front of the gantry facing the table. In this position, the highest 𝐶𝐶(𝐸) was 1.02E + 04 μSv / Gy.cm (0.01%), in the situation where the professional accompanies 10-year-old patients. In the second position, when the professional is located behind the side-facing gantry, the 𝐶𝐶(𝐸) were 31% and 10% lower when monitoring patients aged 1 to 10 years, respectively. The organs of male professionals with the highest conversion rates for equivalent doses (CC(𝐻t )) were colon, stomach, breasts, testicles and liver. For the female professional, eyes and thyroid are also added, excluding the testicles. The use of personal protective equipment (PPE) was also evaluated, and it is concluded that the use of PPE led to a 93% dose reduction, being efficient in the radiological protection of professionals who accompany patients during the CT examination.