United States Nuclear Regulatory Commission - Protecting People and the Environment

U.S. Nuclear Regulatory Commission

Question 150: 10 CFR 20.1003 defines tissue monitoring

depths of 0.007, 0.3, and 1 cm for shallow, eye, and

deep-dose, respectively; (a) Is it important to measure at

(or extrapolate the measurements to) these exact depths?

(b) could the eye and deep-dose both be determined at 0.3


Answer: See the "general response" in the answer to

Question 149.

a) As under the old Part 20, it is important to measure

(or to extrapolate measurements to, or otherwise assess the

dose equivalent) at a reasonable approximation of these


(b) No. The deep-dose equivalent is, by definition, the

dose equivalent at a depth of 1 cm, not 0.3 cm. However,

the dose at 0.3 cm (eye dose) would usually be a

conservative approximation (overestimate) of the dose at 1

cm deep-dose). (References: 10 CFR 20.1003)

Page Last Reviewed/Updated Thursday, March 29, 2012