U.S. Nuclear Regulatory Commission
Question 9: A licensee monitors a worker for both external
and internal exposure under §20.1502, but the internal
exposure for the year is less than 10% of the dose limit.
Does the licensee add it to the external exposure?
Answer: If both internal and external doses were required
to be monitored (see 10 CFR 20.1502 for these
requirements), then they must be summed. If only the
internal or external dose required monitoring, then they
don't have to be summed. (References: 10 CFR 20.1202, 10