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https://www.arca.fiocruz.br/handle/icict/659
PARAMETRIC ANALYSIS OF A BIOKINETIC MODEL: A CONTRIBUTION TO THE STUDY OF MODEL RELIABILITY
Affilliation
Instituto de Radioproteção e Dosimetria. Rio de Janeiro, RJ, Brasil.
Universidade do Estado do Rio de Janeiro. Instituto de Biologia. Rio de Janeiro, RJ, Brasil.
Fundação Oswaldo Cruz. Instituto de Comunicação e Informação Científica e Tecnologia em Saúde. Rio de Janeiro, RJ, Brasil.
Universidade do Estado do Rio de Janeiro. Instituto de Biologia. Rio de Janeiro, RJ, Brasil.
Fundação Oswaldo Cruz. Instituto de Comunicação e Informação Científica e Tecnologia em Saúde. Rio de Janeiro, RJ, Brasil.
Abstract
Models for simulating radionuclide distribution in the human body involve assumptions on the biokinetic behaviour of the material. An important problem in biokinetic modelling is the correct assignment of transfer coefficients and biological half-lives to tissue compartments. The purpose of this study is the analysis of the variations of the radionuclide contents in the tissue compartments related to variations in the transfer coefficients from blood to the compartments and to variations in the compartments' biological half-lives. A generalised systemic recycling model, consisting of four tissue compartments and two excretion pathways, was used for the parametric analysis. A continuous intake directly to the blood was chosen for this study. Activities in the compartments were calculated for different times, following random selection of the transfer coefficients and half-lives. A computer code was developed to perform the random selection of parameters. Three different case studies were analysed, where different intervals of variation of half-lives in the four compartments were chosen: (a) the same range of variation was assigned to all compartments, (b) the intervals were chosen so that one compartment had a significantly longer half-life than the others, and (c) one compartment had a significantly shorter half-life than the others. Two cases for the intervals of variation of the transfer coefficients were investigated: (a) the same range for the variation of all transfer coefficients from blood to compartments was assumed, and (b) the interval of the variation of one transfer coefficient was significantly larger than the others. A multiple regression analysis method was applied to analyse the results. In this paper the detailed results of the parametric analysis are presented.
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