Analysis of a case of internal contamination with 242Cm

During the preparation of targets for the mass spectrometer some 242Cm escaped from the preparation box resulting in a contamination of the laboratory air and of subsequent ingestion of radioactivity by the technician concerned. Nose wipe tests were taken immediately after the incident and faecal and urine samples during the following week. Air sampling filters located in three places in the laboratory were changed immediately and then at regular intervals. The size distribution of the particles was calculated from autoradiographs made from the filter samples. From the results of these analyses the quantity ingested in the respiratory tract was determined using the ICRP "Lung Model" as a guide. The distribution of the ingested material in the body organs was then estimated from the data in Publication 2 (1959) of the ICRP. Although the quantities involved predicted an internal contamination far below the maximum permissible values, this detailed analysis was carried out as an opportunity for testing the "Lung Model" in the case of Curium inhalation. Interpretation and comparison of air filter sampling data with results of nose wipe and faecal tests suggest that the ICRP lung model may serve as a useful guide to estimate the approximate level of an internal contamination after inhalation exposure to 242Cm.