Under 10 CFR 20 Appendix B, if an organ is identified, the internal dose limit is based on which quantity?

• A. CEDE (Stochastic) limit
• B. CDE (Non-stochastic) limit
• C. ALI
• D. DAC

Answer: (B)

When internal dose is being assessed, two kinds of dose limits are used: one for stochastic, whole-body risk, and one for non-stochastic, organ-specific effects. If an organ is identified as receiving radiation, the limit is set to the Committed Dose Equivalent for that organ. This reflects the deterministic, organ-specific effects and ensures that the dose to that particular tissue stays within safe limits.

CEDE, Committed Effective Dose Equivalent, combines doses to all organs to represent overall stochastic risk to the body, not the specific organ. ALI (Annual Limit on Intake) relates to how much material can be ingested or inhaled in a year to keep limits, and DAC (Derived Air Concentration) is used for airborne contaminants.

So, the internal dose limit for an identified organ is based on the Committed Dose Equivalent for that organ.