Occupational Intakes of Radionuclides Part 1 - ICRP

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DRAFT REPORT FOR CONSULTATION
Type S deposited materials that are relatively insoluble in the
respiratory tract. (Slow absorption.)
Type V deposited materials that, for dosimetric purposes, are
assumed to be instantaneously absorbed into body fluids from the respiratory
tract: only certain gases and vapours. (Very fast absorption)
Uptake. See also ‘Intake’
Activity that enters body fluids from the respiratory or alimentary tract or
through the skin.
Terms for Bioassay Interpretation
Action level
A pre-set level above which some remedial action should be considered.
Activity
The number of nuclear transformations per unit time (s) of a radioactive
material. The SI unit of the activity is the becquerel (Bq): 1 Bq = 1 s -1
Bioassay
Any procedure used to determine the nature, activity, location or retention of
radionuclides in the body by direct (in vivo) measurement or by indirect (in
vitro) analysis of material excreted or otherwise removed from the body.
Bioassay function
In this report series: A set of tabulated values m(t) predicted by the reference
biokinetic models describing the time course of the activity in the body
(“retention function”) or the activity excreted via urine or faeces (“excretion
function”) following a single intake at time t = 0. In general, the retention
functions represent the body or organ activity at the time t after the intake,
whereas the excretion functions represent the daily excretion: the integral of
the instantaneous excretion rate from (t – 1) until t, where t is the number of
days after a single intake (integer).
Decision Threshold
Fixed value of a measured quantity that, when exceeded by the result of an
actual measurement quantifying a physical effect (e.g. the presence of a
radionuclide in a sample), may be taken to indicate that the physical effect is
present. The decision threshold is the critical value of a statistical test for the
decision between the hypothesis that the physical effect is not present and the
alternative hypothesis that it is present. When the critical value is exceeded by
the result of an actual measurement, this is taken to indicate that the
hypothesis should be rejected. The statistical test is designed in such a way
that the probability of wrongly rejecting the hypothesis (Type I error) is at
most equal to a given value, α. The decision threshold is an a posteriori
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