The ICRP has brought series (in
three parts) of draft reports “Occupational Intake of Radionuclides” for
consultation. The documents are replacing the Publication 30 series and
Publication 68 to provide revised dose coefficients for occupational intakes of
radionuclides (OIR) by inhalation and ingestion. The revision was necessary in
view of the fact that 2007 Recommendations of the ICRP (ICRP Publication 103) introduced
changes to the radiation weighting
factors used in the calculation of equivalent dose to organs and tissues and
also changes to the tissue weighting factors used in the calculation of effective
dose. The revision adopts reference anatomical computational phantoms (that is,
models of the human body based on medical imaging data), in place of the
composite mathematical models that have been used for all previous calculations
of organ doses.
The ICRP Publication 103
also clarified the need for separate calculation of equivalent dose to males
and females and sex-averaging in the calculation of effective dose (ICRP,
2007). In the revision of dose coefficients, the opportunity has also been
taken to improve calculations by updating radionuclide decay data (ICRP, 2008)
and implementing more sophisticated treatments of radiation transport (ICRP,
2010) using the ICRP reference anatomical phantoms of the human body (ICRP,
2009).
The revised
dose coefficients have been calculated using the Publication 100 Human
Alimentary Tract Model (HATM) and a revision of the Publication 66 Human
Respiratory Tract Model (HRTM) which takes account of more recent data. In
addition, information has been provided on absorption to blood following
inhalation and ingestion of different chemical forms of elements and their
radioisotopes. Revisions have been made to many models for the systemic bio-kinetics
of radionuclides absorbed to blood, making them more physiologically realistic
representations of uptake and retention in organs and tissues, and of
excretion.
The reports
in this series provide data for the interpretation of bioassay measurements as well
as giving dose coefficients, replacing Publications 54 and 78. This report provides
some guidance on monitoring programmes and data interpretation (source: www.ICRP.org).
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