

DOESTD112898
Type of Radiation Exposure
Annual Limit
Occupational Exposures
Stochastic Effects
5rem total effective dose equivalent
from external sources and the CEDE
intakes received during the year
NonStochastic Effects
Lens of eye
15rem dose equivalent
Extremity
50rem dose equivalent
Skin
50rem dose equivalent
Individual organ tissue
50rem dose equivalent
Embryo/fetus of a Declared Pregnant Worker
Gestation period
0.5rem dose equivalent
Planned Special Exposure
Event plus Annual
5rem total effective dose equivalent
Occupational exposure
Minors
0.1rem TEDE
6.1.2
Operational Quantities
Because of the difficulties in determining effective dose equivalent from direct
measurements, the concept of operational quantities has been introduced to be
more closely related to measurable quantities. Operational quantities include
ambient dose equivalent used for area monitoring and personal dose equivalent
used for personnel dosimetry. Operational quantities are designed to be a
conservative estimator of effective dose equivalent, i.e., the values of the
operational quantities will be equal to or higher than the effective dose equivalent
specified for the limiting quantities.
The ambient dose equivalent, H* (d), is the dose equivalent at a depth, d, in a 30
cmdiameter sphere of tissue, where a) the radiation field has the same fluence
and energy distribution as the point of reference for the measurement and b) the
fluence is unidirectional (i.e., the sphere can be viewed as being in an aligned
radiation field). Most survey instruments are designed to measure ambient dose
equivalent, and international standards are based on the ambient dose equivalent
concept. The depth of interest is 1 cm of soft tissue, as specified in 10 CFR
835.2.
The personal dose equivalent, Hp(d), is the dose equivalent in soft tissue at the
appropriate depth, d, below a specified point on the body. Obviously, personnel
dosimeters should be calibrated in terms of personal dose equivalent.
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