Avaliação radiodosimétrica através do código MCNP-5 da radiosteoplastia em tumores ósseos nos membros

Abstract

RESUMOO presente trabalho aborda a dosimetria computacional de um caso clínico envolvendo uma criança com tumor ósseo na fíbula, onde as respectivas imagens tomográficas foram digitalizadas e tratadas no programa SISCODES, gerando assim o modelo de vóxel 3D, representativo do caso clínico, que foi transferido para o código Monte Carlo, MCNP-5. Características nucleares da fonte incorporada no compósito radioativo são apresentadas com sua respectiva atividade específica. Os resultados obtidos da distribuição espacial de dose oriunda da emissão gama do Sm-153 foi uma taxa de dose de 9,02.10 -5 GyhMBq-1 e uma dose acumulada de 6,23.10 -3 GyhMBq -1 . Portanto, 7400 MBq produzirá uma dose no tumor de 47 Gy, compatível possivelmente com o controle local do tumor. Pode-se concluir que a adequada distribuição espacial de dose suporta o uso do protocolo denominado radiosteoplastia no tratamento de tumores ósseos de membros superiores e inferiores. A radiosteoplastia é uma técnica que está sendo avaliada no NRI -Núcleo de Radiações Ionizantes da UFMG. Trata-se de um procedimento que consiste na injeção de um biomaterial radioativo no interior da estrutura óssea afetada pelo câncer, objetivando redução da dor, aumento da resistência de carga naquela estrutura e, principalmente, o controle do tumor ou da metástase de forma local. Palavras chave:Dosimetria computacional, radiosteoplastia, tumor ósseo, MCNP. Radiodosimetric Evaluation through MCNP-5 Code of the Radiosteoplasty on Bone Tumors in Members ABSTRACTThe present paper addresses the computational dosimetry of a clinical case involving a child with tumor on the fibula, whose tomographic images were digitalized and manipulated by the SISCODES program, in order to generate a 3D voxel model, representative of the clinical case. Later, it was plugged in to the Monte Carlo MCNP-5 code and the model was used for absorbed dose prediction. Nuclear features of the cement incorporating the radionuclide composite were presented with its respectively specific activity. The spatial dose rate distribution from the gamma emission of the Sm-153 was 9.02 10 -5 GyhMBq -1 and the imparted absorbed dose was 6.23 10 -3 GyhMBq -1. Therefore, 7400 MBq produced a tumor dose of 47 Gy, suitable for the local tumor control. As conclusion, an adequate spatial dose distribution supports the application of this protocol, namely radiosteoplasty, as a therapy for bone tumors on the superior and inferior members. The radiosteoplasty is a technique that is in development in the research group NRI-Núcleo de Radiações Ionizantes at UFMG. It is a procedure that consists of the injection of a radioactive biomaterial into the bone structure affected by cancer, following pain reduction, structural resistance increasing, and mainly tumor or metastasis control in situ.

Scientific knowledge management about Monte Carlo method: a bibliometric analysis on IRD Postgraduate Program in Radiation Protection and Dosimetry

“…Although the initial ideas for applying the method date back to the 16th century, its application became possible with the advent of computing. The first noteworthy application occurred in the project of controlled energy production through nuclear fission, during the Second World War [4].…”

“…In the study of particle transport, for example, the MC consists of following each of the numerous particles along their path to some final event, such as absorption, escape, etc. [4].…”