Committed dose

The committed dose is the organ equivalent dose or effective dose resulting from the intake of a radionuclide into the human body (incorporation) and calculated over a certain period of time beginning after the incorporation (hence the name committed dose). This period of time is usually defined in such a way that the committed dose is calculated up to the fictitious end of life.

• The committed organ equivalent dose is obtained by using biokinetic models to calculate the organ equivalent dose rate acting on an organ (organ equivalent dose per unit of time) and integrating this from the time of incorporation over the specified period of time, i.e. dividing the specified period of time into very small time intervals and adding up the organ equivalent doses in these time intervals.
• The committed effective dose is obtained by first multiplying the committed organ equivalent doses by the respective tissue weighting factor and adding the weighted committed organ equivalent doses.

For children, the calculation is up to an age of 70 years from the time of incorporation. For adults, the calculations are uniformly based on a period of 50 years until the fictitious end of life, irrespective of age, i.e. adults are treated as 20-year-old persons for dosimetric purposes. The calculated committed dose for adults is thus overestimated.

There is a special feature for the unborn or breastfed child: Here, the committed dose of the unborn or breastfed child is calculated as a result of the incorporation of radionuclides by the mother.

Unit

The unit of the committed dose (committed organ equivalent dose or committed effective dose) is the sievert (Sv). One sievert corresponds to 1 joule per kilogram (J/kg). In practical radiation protection, fractions of the dose unit are generally used, for example millisievert (mSv) or microsievert (µSv).