Effective dose coefficient
A measure of the hazard of nuclear material is provided by the toxicity and in particular its radiotoxicity arising from its radioactive “quality” rather than the chemical toxicity. The radiotoxicity of a nuclide is determined by its effective dose coefficient e(T), which accounts for radiation and tissue weighting factors, metabolic and biokinetic information. The quantity T is the integration time in years following intake. For adults, the integration time is 50 years, such that the radiotoxicity (in Sievert, Sv) or committed effective dose resulting from intake of a particular nuclide is the product of the effective dose coefficient (units Sv/Bq) and the activity (in Bq) of that nuclide i.e.
Committed effective dose = Activity · e(50).
The two main pathways for intake of a radionuclide are through ingestion and inhalation. Accordingly one can differentiate between the ingestion dose coefficient eing(50) and the inhalation does coefficient einh(50) for inhalation.
The effective dose coefficients given in the Nucleonica databases are taken from:
- Dose Coefficients for Intakes of Radionuclides by Workers, ICRP Publication 68, Ann. ICRP 24 (4), 1994
- Age-dependent Doses to the Members of the Public from Intake of Radionuclides - Part 5 Compilation of Ingestion and Inhalation Coefficients, ICRP Publication 72, Ann. ICRP 26 (1), 1995