Effective methods for monitoring internal contamination among workers handling radioactive materials in various fields.

This study aimed to develop effective methods for monitoring internal contamination among workers handling radioactive materials in various fields. A total of 160 workers from nuclear power plants, medical institutions, military units, and educational/research institutions were included in the study. The monitoring methods included urinalysis and whole-body counting (WBC) using a mobile radio bioassay laboratory (MRL). Gamma-emitting radionuclides were monitored using the MRL WBC system, and a separate pretreatment procedure was used for tritium measurement in urine samples. Gross beta-screening was performed using a liquid scintillation counting system. The results were evaluated on the basis of the established screening criteria and compared with the dose limits. Additionally, tritium concentrations in the bodies of workers in the vicinity of a heavy-water reactor was analysed to assess the association between tritium concentration and occupation. The results showed a wide distribution of tritium concentrations. Workers involved in fuel and maintenance tasks demonstrated the maximum exposure. Workers in medical facilities showed low levels of internal contamination, which was primarily related to tasks involving radioactive isotopes. Military personnel involved in equipment repair showed significant tritium contamination due to damage during repairs. Workers in educational and research institutions in general had low levels of internal contamination.
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