Occupational Intakes of Radionuclides Part 1 - ICRP

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DRAFT REPORT FOR CONSULTATION
economic factors. The main factors that determine the dosimetric performance of the
monitoring programme relate to the characteristics of the material to which a worker
may potentially be exposed (normally by inhalation). These are:
the radiations emitted by the radionuclide and its progeny;
the effective half-life of the radionuclide;
the respiratory tract deposition characteristics of the aerosol;
the respiratory tract and alimentary tract absorption characteristics of the
material;
the retention in the body or the excretion rate from the body as a function of the
time between intake and measurement;
any preferential deposition in particular body organs and tissues and subsequent
retention in those organs;
any significant differences between the biokinetic behaviour of a parent
radionuclide and its progeny;
the excretion pathway (e.g. urine, faeces);
the technical feasibility of the measurement.
(275) The dosimetric performance of the monitoring programme may be assessed by
considering the effect of these factors on the accuracy of assessed doses and on the
sensitivity associated with the monitoring programme, which can be quantified in
terms of the assessed minimum detectable dose (Carbaugh, 2003; Etherington et al,
2004a, 2004b). One approach to optimising the design of a monitoring programme is
to assess how different choices for the type, number and time period of measurements
affect uncertainties in assessed dose.
5.3 Categories of Monitoring Programmes
(276) Four categories of monitoring programmes can (generally) be defined:
Routine monitoring is performed where intakes by workers are probable in
anytime during normal operations, or where accidental intakes could otherwise
remain undetected.
Special monitoring is performed after actual or suspected abnormal events.
Confirmatory monitoring is carried out to demonstrate that working conditions
are satisfactory, and that there is no need for routine individual monitoring. It could
consist of occasional individual monitoring measurements.
Task-related monitoring is carried out to provide information about a
particular operation.
(277) The four categories of monitoring are not mutually exclusive; in fact there can
be considerable overlap. For example, an effective routine monitoring programme not
only provides reliable data on individual worker exposures and doses, but can also be
used to demonstrate that the work environment and work procedures are under
satisfactory control.
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