title: Dependence of the dose estimate on the time pattern of intake by the example of tritiated water intakes.
abstract: The uncertainties related to activity measurement and time pattern of intake in routine monitoring of internal exposure are considered through the example of tritiated water intakes. For this purpose, a combination of intake-to-bioassay and bioassay-to-intake calculations with Monte Carlo integration technique is introduced as a method of investigation. The time pattern of intake and the measured activity are defined as random input quantities. The probability density functions (PDFs) of the input quantities are defined and a Monte Carlo integration is performed to obtain the PDF of the output quantity which is either the value of intake estimated from a measured value of activity or the estimated activity from a given value of intake. Different possible estimates of the intake are considered: some represent the parameters of the PDF of the output quantity, others are derived from the commonly used constant chronic, I(CC), and mid-point, I(1/2), methods. The combinations of activity and intake estimates that would provide a stable estimate of the initial intake in intake-to-bioassay and bioassay-to-intake calculations were studied. Several intake estimates satisfying this requirement can be chosen depending on the task to be solved by adjusting the proper activity estimate.
authors.affiliation: IRSN--Institute for Radiological Protection and Nuclear Safety, Internal Dosimetry Department, IRSN/DRPH/SDI, BP 17, F-92262 Fontenay-aux-Roses Cedex, France. andrey.molokanov@irsn.fr
authors.forename: A
authors.initials: A
authors.lastname: Molokanov
authors.forename: E
authors.initials: E
authors.lastname: Blanchardon
mesh_terms: D001681:Biological Assay / Q000379:methods*; D001822:Body Burden; D003198:Computer Simulation; D006801:Humans; D008954:Models, Biological; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors; D014316:Tritium / Q000032:analysis / Q000493:pharmacokinetics*; D014867:Water / Q000032:analysis / Q000378:metabolism*
chemical_list: D014867:Water; D014316:Tritium