where radioactive materials are handled for less than 8 hr, during which
time the materials are constantly attended.
Occupational Dose Limits
The annual limit of the occupational dose to an individual adult is the more
limiting of (a) TEDE of 5 rem (0.05 Sv) or (b) the sum of the deep-dose
equivalent and the committed dose equivalent to any individual organ or
tissue other than the lens of the eye being equal to 50 rem (0.5 Sv). It should
be noted that there is no lifetime cumulative dose limit in the revised
10CFR20, although the NCRP recommends a lifetime cumulative dose of
1 rem (10 mSv) ×age in years.
The annual limit on the occupational dose to the lens of the eye is 15 rem
(0.15 Sv).
The annual limit of the occupational dose to the skin and other extrem-
ities is the shallow-dose equivalent of 50 rem (0.5 Sv).
Depending on the license conditions, both internal and external doses
have to be summed to comply with the limits. A licensee may authorize
under planned special proceduresan adult worker to receive additional dose
in excess of the prescribed annual limits, provided no alternative procedure
is available. The total dose from all planned procedures plus all doses in
excess of the limits must not exceed the dose limit (5 rem or 50 mSv) in a
given year, nor must it exceed five times the annual dose limits in the indi-
vidual’s lifetime.
Radiation Protection 273Fig. 16.1. Various radiation caution signs and labels.