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Re: Effective Dose Equivalent




>Is there an upper limit of dose above which the concept of equivalent dose
>does not apply?

Absolutely.  ICRP 60 defines Equivalent Dose (average dose to an organ or
tissue) as the absorbed dose weighted by radiation weighting factors, where
"the value of the radiation weighting factor ...(is).. representative of
values of the relative biological effectiveness of that radiation in
inducing stochastic effects at low doses."  Following on from that,
Effective Dose is the weighted sum of the Equivalent Doses of all the
organs and tissues of the body.  The ICRP notes "... equivalent dose and
effective dose ... provide a basis for estimating the probability of
stochastic effects only for absorbed doses well below the thresholds for
deterministic effects."
Incidentally, I was wondering if there any move in the US to adopt the
ICRP's 1990 update from EDE to effective dose, with its wider range of
tissue weighting factors?

Jocelyn Towson
Royal Prince Alfred Hospital
Sydney

jtowson@nucmed.rpa.cs.nsw.gov.au