RESUMO
Lung tissues from workers at the Mayak Production Association were examined to determine the distribution of plutonium (Pu) activity in various lung compartments. Stereological sampling methods and autoradiography were used. Pu particles were identified by microscopic examination of autoradiographs and localised in one of six normal anatomic sites and two sites of fibrosis (parenchymal, non-parenchymal). Particle activity was determined by counting the number of tracks emanating from the particles. Over 50% of the Pu activity was localised in sites of fibrosis, which had significantly higher than average activity for the lung. Over 40% of the activity was in lung parenchyma. Activity in the bronchovascular interstitium was significantly lower than average. These results support the hypothesis that Pu activity is not uniformly distributed in the lung, with long-term retained particles concentrated in scars of the lung. The results may significantly affect estimates of dose from inhaled Pu.
Assuntos
Poluentes Radioativos do Ar/farmacocinética , Exposição por Inalação/análise , Pulmão/metabolismo , Pulmão/patologia , Exposição Ocupacional/análise , Plutônio/farmacocinética , Medição de Risco/métodos , Adulto , Idoso , Poluentes Radioativos do Ar/análise , Carga Corporal (Radioterapia) , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Plutônio/análise , Centrais Elétricas , Doses de Radiação , Radiometria/métodos , Federação Russa , Distribuição TecidualRESUMO
Results obtained in a study of the microscopic distribution of plutonium in the lungs of deceased Pu workers from the Mayak Production Association showed that the long-term retention of Pu was greater than predicted by the current ICRP 66 respiratory tract dosimetry model (HRTM). These data were therefore applied to the HRTM by modifying selected parameters, namely the transfer rate of Pu from the transformed state compartment and the fraction of Pu that transfers to the bound state compartment. Invoking the latter compartment into the modelling allowed a better representation of the long-term Pu retention as well as providing a convenient means of describing the workplace-specific characteristics of the different Pu aerosols found in the Mayak plant. In particular, the present model describes a significantly greater long-term retention of Pu nitrate aerosols in the lung compared with the Type M default.