Which workers should be monitored for internal deposition of radionuclides?

Which workers should be monitored for internal deposition of radionuclides?

• A. People working with sealed sources.
• B. People working with unsealed radioactive materials that have the potential to intake radioactive material exceeding 2% of ALI.
• C. All workers.
• D. Only workers who handle external radiation detectors.

Answer: (B)

Focusing on who can actually accumulate material inside the body is key. Internal deposition monitoring is required for workers who handle unsealed radioactive materials and thus have the potential to inhale or ingest radioactive substances at levels that exceed a small fraction of the annual limit on intake, typically about 2% of the ALI. When there’s a chance of intake above that threshold, bioassay or in vivo counting is used to detect any internal contamination early and manage it appropriately. Sealed sources are designed to prevent leakage, so they generally don’t pose an internal exposure risk and don’t automatically require internal monitoring. External radiation detectors measure dose from outside the body, not internal uptake, so those who only work with external detectors are not the primary group for internal deposition monitoring.

Focusing on who can actually accumulate material inside the body is key. Internal deposition monitoring is required for workers who handle unsealed radioactive materials and thus have the potential to inhale or ingest radioactive substances at levels that exceed a small fraction of the annual limit on intake, typically about 2% of the ALI. When there’s a chance of intake above that threshold, bioassay or in vivo counting is used to detect any internal contamination early and manage it appropriately. Sealed sources are designed to prevent leakage, so they generally don’t pose an internal exposure risk and don’t automatically require internal monitoring. External radiation detectors measure dose from outside the body, not internal uptake, so those who only work with external detectors are not the primary group for internal deposition monitoring.