Committed effective dose equivalent (CEDE)

Committed Effective Dose Equivalent (CEDE)

The Committed Effective Dose Equivalent (CEDE)is a measure used in radiological protection to quantify the risk of exposure to radioactive materials that have been ingested or inhaled. It represents the sum of the effective dose equivalents over a specified period, typically 50 years for adults and up to age 70 for children, following the intake of radioactive substances.

Definition

The CEDE is calculated by considering the type and energy of radiation emitted by the radionuclide, the biological half-life of the radionuclide in the body, and the sensitivity of different organs and tissues to radiation. It is expressed in sieverts (Sv), which is the SI unit for dose equivalent.

The formula for calculating the CEDE is:

\[ CEDE = \sum_{T} w_T \cdot H_T(t) \]

where: - \( w_T \) is the tissue weighting factor for tissue \( T \), reflecting the relative sensitivity of the tissue to radiation. - \( H_T(t) \) is the committed dose equivalent to tissue \( T \) over time \( t \).

Importance in Radiological Protection

The CEDE is crucial in assessing the long-term health risks associated with internal contamination by radioactive substances. It helps in:

• Risk Assessment: Estimating the potential health effects, such as cancer, from exposure to radioactive materials.
• Regulatory Compliance: Ensuring that occupational and public exposures remain within the limits set by regulatory bodies such as the ICRP.
• Medical Management: Guiding the treatment and monitoring of individuals exposed to radioactive materials.

Calculation and Monitoring

To calculate the CEDE, one must:

1. Identify the Radionuclide: Determine the type of radioactive material involved in the exposure. 2. Measure the Intake: Quantify the amount of radionuclide inhaled or ingested. 3. Use Biokinetic Models: Apply models that describe the distribution and retention of radionuclides in the body. 4. Apply Dose Coefficients: Use dose coefficients provided by organizations like the ICRP to convert intake into dose.

Monitoring of CEDE involves regular assessment of individuals who may be exposed to radioactive materials, using techniques such as bioassay and whole-body counting.

Also see

• Effective dose
• Radiation protection
• Internal dosimetry
• Sievert
• International Commission on Radiological Protection