STANDARDIZATION OF THE FRICKE GEL DOSIMETRY METHOD AND TRIDIMENSIONAL DOSE EVALUATION USING THE MAGNETIC RESONANCE IMAGING TECHNIQUE / Padronização do método de dosimetria Fricke gel e avaliação tridimensional de dose empregando a técnica de imageamento por ressonância magnética

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

This study standardized the method for obtaining the Fricke gel solution developed at IPEN. The results for different gel qualities used in the preparation of solutions and the influence of the gelatin concentration in the response of dosimetric solutions were compared. Type tests such as: dose response dependence, minimum and maximum detection limits, response reproducibility, among others, were carried out using different radiation types and the Optical Absorption (OA) spectrophotometry and Magnetic Resonance (MR) techniques. The useful dose ranges for Co 60 gamma radiation and 6 MeV photons are 0,4 to 30,0 Gy and 0,5 to 100,0 Gy , using OA and MR techniques, respectively. A study of ferric ions diffusion in solution was performed to determine the optimum time interval between irradiation and samples evaluation; until 2,5 hours after irradiation to obtain sharp MR images. A spherical simulator consisting of Fricke gel solution prepared with 5% by weight 270 Bloom gelatine (national quality) was developed to be used to three-dimensional dose assessment using the Magnetic Resonance Imaging (MRI) technique. The Fricke gel solution prepared with 270 Bloom gelatine, that, in addition to low cost, can be easily acquired on the national market, presents satisfactory results on the ease of handling, sensitivity, response reproducibility and consistency. The results confirm their applicability in the threedimensional dosimetry using MRI technique.

ASSUNTO(S)

dosimetria fricke gel imageamento por ressonância magnética (irm). gelatina 270 bloom dosimetria fricke gel imageamento por ressonância magnética (irm). gelatina 270 bloom

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