ICRP-60 and "H"

["Scott O. Schwahn" <schwahn@CEBAF.GOV>]

ICRP-60 changes in terminology and notation resulted in the following (I
will use the underscore (_) to indicate subscripts):

Equivalent Dose (H_{T,R} or H_T) replaced dose equivalent.  Radiation
weighting factor , w_R, replaced the quality factor.  

H_{T,R} = (w_R)(D_{T,R}) and 
H_T = sum over all R [(w_R)(D_{T,R})]

Effective Dose, E, replaced effective dose equivalent:

E = sum over all T [(w_T)(H_T)]
  = sum over all R [(w_R)(sum over all T [(w_T)(D_{T,R})])]
  = sum over all T [(w_T)(sum over all R [(w_R)(D_{T,R})])]

There are also modified names for others: committed equivalent dose replaced
committed dose equivalent; committed effective dose replaced committed
effective dose equivalent.

Although radiation weighting factors (w_R, formerly quality factor) did not
change, tissue weighting factors (w_T) changed and included 6 additional
tissues beyond those in ICRP-26 (colon, stomach, bladder, liver, esophagus,
and skin).  One should note that there is a rather large difference between
the tissue weighting factors in ICRP-60 vs. ICRP-26, especially for breast.
The colon  and stomach have rather large weighting factors (0.12 each).

Sorry about all the parentheses.  I hope that was clear enough.

Scott O. Schwahn, CHP
Operational Health Physicist
Thomas Jefferson National Accelerator Facility
(804)249-7551 (w)
(804)249-7363 (fax)
schwahn@cebaf.gov

Previously posted:
--------------------------------------------------------
>Dose equivalent (ie prior to ICRP 60) and Equivalent dose (ie after ICRP 60)
>are "almost" the same. The difference lies in their definition. Dose
>equivalent used radiation Quality Factors which were broadly based on the
>Linear Energy Transfer of the radiation in question. Equivalent dose uses
>radiation weighting factors which are more or less the same as Q factors but
>the numbers have changed slightly in some cases (I think!!). So, strictly
>speaking, Dose equivalent and Equivalent dose are not the same, but for all
>intents and purposes may be taken as the same (does that make sense to you??).