Under 10 CFR 20 Appendix B, if an organ is NOT identified, the internal dose limit is based on which quantity?

Under 10 CFR 20 Appendix B, if an organ is NOT identified, the internal dose limit is based on which quantity?

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

Answer: (A)

When the distribution of the radionuclide among organs isn’t known, regulatory limits are applied to the overall risk rather than to a single tissue. That means using the committed effective dose equivalent (CEDE), which combines doses to all tissues with their weighting factors to reflect stochastic health risks like cancer. CEDE represents the total internal dose risk over the committed period, even when you can’t specify which organ received the dose. In contrast, committed dose equivalent (CDE) would apply to a specific organ if that organ were identified, and ALI or DAC relate to intake or air concentration limits, not to the organ-unknown scenario. So the internal dose limit in this case is based on CEDE.

When the distribution of the radionuclide among organs isn’t known, regulatory limits are applied to the overall risk rather than to a single tissue. That means using the committed effective dose equivalent (CEDE), which combines doses to all tissues with their weighting factors to reflect stochastic health risks like cancer. CEDE represents the total internal dose risk over the committed period, even when you can’t specify which organ received the dose. In contrast, committed dose equivalent (CDE) would apply to a specific organ if that organ were identified, and ALI or DAC relate to intake or air concentration limits, not to the organ-unknown scenario. So the internal dose limit in this case is based on CEDE.