Avaliação das exposições médicas e ocupacionais em cirurgias ortopédicas por meio do método Monte Carlo

• Autor(a) principal: Santos, Felipe Amorim
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: http://ri.ufs.br/jspui/handle/riufs/8134
• topic: Física; Raios X; Dosimetria; Simuladores antropomórficos computacionais; Método de Monte Carlo; Física médica; Radiologia; Risco de câncer; Cifoplastia; Cirurgia ortopédica; CIENCIAS EXATAS E DA TERRA::FISICA

Clinical settings for vertebral compression fracture surgery were virtually modeled to estimate equivalent, effective, and cancer risk values normalized by the KAP (Kerma Product Area) for the patient and surgeon. This surgery is known as kyphoplasty and involves the use the equipament of type arch C, which provides real-time imaging and supports the surgeon during needle manipulation and delivery of surgical cement into the fractured vertebra. The radiation transport code used was MCNPX (Monte Carlo N-Particle eXtended) and two dual virtual anthropomorphic simulators: UFHADM and UFHADF (University of Florida Hybrid ADULT Male / Female). Two projections were simulated with seven tube voltage voltages for each. In the same scenario the KAP was calculated at the tube output, providing the calculation of the conversion coefficients (E/KAP, HT/KAP and RC/KAP). From the knowledge of experimental values of KAP and the results presented in this study, it was possible to estimate absolute values of equivalent, effective dose and cancer risk for different exposure conditions. In this work, scenarios were developed with and without the surgical table, in order to compare it with the existing data in the literature. The absence of the bed in the scenario promoted a percentual increase of 56% in the effective doses of patients in relation to the scenarios calculated with the bed. Regarding the surgeon, considering all projections, the use of personal protective equipment reduced the effective dose, on average, between 66-68%; while the use of the UTS reduced this same greatness by 2-5%. In relation to the study of cancer risk, colon and lung presented as a higher risk organ for the patient and surgeon, respectively. For the simulator undergoing kyphoplasty (pacient), considering a beam of 70 kVp, KAP of 5.5 Gy.cm2 and a effective cancer risk coefficient calculated in this work of 3.77 Gy-1.cm-2, it was estimated 21 cancer deaths were estimated, considering a universe of 106 cases. The data obtained in this work emphasize the importance of elaborating virtual scenarios that resemble clinical scenarios, generating E/KAP, HT/KAP and RC/KAP values that are closer to the real values.