Re: Effective Dose Equivalent

[Ccja@aol.com]

Actually, I believe that it was the ICRP's intent that the tissue weighting
factors be used whenever the body was non-uniformly irradiated. We have, for
instance, a problem with occupational dosimetry in clinical medicine, because
the regulations are written so that we are constrained to pretend that a dose
to, say, the head, represents the equal in stochastic risks of a "true",
uniform external irradiation. This is plainly not the case, when the exposed
individual (to x-rays of not more than about 40 keV effective energy, and
usually much less, due to prior Compton interaction), is sheathed in an apron
of 0.5mm Pb-equivalency. A number of schemes have been proposed over the
years, but we had no authoritatively definitive guidance until the
publication of NCRP Report 122, Use of Personal Monitors to Estimate
Effective Dose Equivalent and Effective Dose to Workers for External Exposure
to Low-Let Radiation, last December. All medical hp's should obtain a copy of
this much-needed statement.

The Sv is, though, a pretty wraithlike sort of beast, when looked at closely.
We have a long way to go to a hard and fast, scientific, definition of it.