Uncertainty in estimated intake for routine lung monitoring of Pu/Am

In routine monitoring of radiation workers to detect internal contamination due to Pu/Am, it is assumed that intake has occurred at the midpoint of the monitoring interval. Radiation worker is normally monitored at the end of the annual monitoring interval, within a span of ±1 month under a routine in vivo monitoring program. An uncertainty is introduced in intake estimation as the time of intake can vary over the entire monitoring interval. In this work, uncertainties introduced in the intake estimation of Type M and S compounds of Pu/Am are evaluated due to unknown time of intake for annual and biennial monitoring frequency.