Assessment of Whole-body Retention to Workers after Accidental Inhalation Of

The intake of radioactive material by workers can occur during the radiopharmaceuticals production or through the nuclear medicine application. The workers which maintain activities in areas with significant risk for the inhalation of radionuclide are routinely monitored to demonstrate that they are receiving adequate protection from internal contamination. The ICRP Publication 78 presents the predicted values of measured quantities (body content) as a function of time, following a single intake by inhalation. Whole-body and thyroid retention have been assessed for two workers who accidentally inhaled aerosols containing 131 I. Specials monitoring were carried out with a 8x4 and 3x3 NaI(Tl) detectors at In Vivo Monitoring Laboratory of IPEN/CNEN-SP. The initial measurement has indicated retention of (77.75 ± 3.32) kBq and (18.34 ± 0.85) kBq after approximately 3.5 h from the incident. Six measurements, whole-body and thyroid, were performed for two weeks after the incident. To estimate the intake, the ICRP biokinetic model was used. The quality of fitting measurement data to model was evaluated. This value is used to determine whether the predicted model is consistent with the measured data. Whole body and thyroid measurements were assumed to be distributed exponentially and lognormally.