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Question 176: 10 CFR 20.1201 (a) (2) (ii) states a limit
of "A shallow-dose equivalent of 50 rem (0.50 Sv) to the
skin or to any extremity." (a) Can a person receive 50
rem shallow dose equivalent to the skin of the lower arm
(extremity) and 50 rem shallow dose equivalent to the upper
arm non-extremity), without having an overexposure? (b)
Can a person receive 50 rem shallow dose equivalent to the
left upper arm, then the same dose to the right upper arm,
without having an overexposure? (c) Can a person receive
50 rem shallow dose equivalent to each extremity during one
year?
Answer: (a) Yes, as long as the total shallow dose
equivalent does not exceed 50 rem in either position. The
skin of the extremity is not considered in the shallow-dose
equivalent limit to the skin of the whole body. The annual
limits are a shallow-dose equivalent of 50 rem (0.50 Sv) to
the skin or to any extremity.
(b) Again, as long as it can be shown that the total
shallow dose equivalent does not exceed 50 rem at any one
location on the skin of the whole body, there is no
violation. If the two different areas of the skin of the
whole body each receives 50 rem total shallow dose
equivalent during the year, then the limit has not been
exceeded.
(c) Yes. The regulation states ". . . or to any
extremity;" therefore, a worker may receive a shallow-dose
equivalent of 50 rem to each of the four extremities.
(Reference: 10 CFR 20.1201, 10 CFR 20.1003, Regulatory
Guide 8.34)