National Council on Radiation Protection and Measurements (NCRP)
Radiation Protection Guidelines: Control of Radiation Dose in the Control Zones

  • The absorbed dose received by an individual emergency responder working in the radiation control zones must be controlled.
  • The cumulative absorbed dose that triggers a decision on whether to withdraw an emergency responder from within or near (but outside) the inner perimeter is 50 rad (0.5 Gy). 1, 2, 3
  • In NCRP Commentary No. 19, the 50 rad (0.5 Gy) cumulative absorbed dose is called the decision dose. 4
  • The cumulative absorbed dose received by an emergency responder while working within or near the inner perimeter must be recorded. 5

1 This recommendation applies only to the early phase of the emergency response when lifesaving or other critical actions may be underway within or near (but outside) the inner perimeter. If the cumulative absorbed dose from activities within the inner and outer perimeters reaches 50 rad (0.5 Gy), a similar decision should be made on whether to remove a responder from within the outer perimeter (or to a low radiation exposure location within the outer perimeter).

2 This cumulative absorbed dose guideline also applies in those rare circumstances when medical staff members are attending to a victim in a lifesaving situation (e.g., the surgical removal of embedded radioactive shrapnel with a very high level of radioactivity.)

3 The absorbed dose and the value obtained with the device used to monitor the absorbed dose should be treated as though it were a whole-body absorbed dose.

4 This guidance is discussed in further detail in Management of Terrorist Events Involving Radioactive Material (NCRP Report No. 138), National Council on Radiation Protection and Measurements, Bethesda, MD, 2001.

5 The cumulative absorbed dose or exposure received by an emergency responder while working outside but near the inner perimeter should be estimated, either from a personal radiation dosimeter worn by the responder or from information on exposure rates and stay times at the locations near the inner perimeter at which the responder worked.



Guidance adapted from:
Key Elements of Preparing Emergency Responders for Nuclear and Radiological Terrorism (NCRP Commentary No. 19), National Council on Radiation Protection and Measurements, Bethesda, MD, December 2005, page 19. Purchase required.

See also:
Responding to a Radiological or Nuclear Terrorism Incident: A Guide for Decision Makers (PDF - 1.61 MB) (NCRP Report No. 165), Bethesda, MD, 2010.