Health Physics Questions and Answers - Question 150

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 cm?

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 depths.

(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)