Occupational Intakes of Radionuclides Part 1 - ICRP

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DRAFT REPORT FOR CONSULTATION
Source Region (rs)
Region of the body containing the radionuclide. The region may be an organ, a
tissue, the contents of the alimentary tract or urinary bladder, or the surfaces of
tissues as in the skeleton and the respiratory tract.
Spongiosa
Term referring to the combined tissues of the bone trabeculae and marrow
tissues (both active and inactive) located within cortical bone cortices across
regions of the axial and appendicular skeleton. Spongiosa is one of three bone
regions defined in the ICRP Publication 110 (ICRP, 2009) reference
phantoms, the other two being cortical bone and medullary marrow of the long
bone shafts. As the relative proportions of trabecular bone, active marrow, and
inactive marrow vary with skeletal site, the homogeneous elemental
composition and mass density of spongiosa is not constant but varies with
skeletal site [see Annex B of ICRP Publication 110 (ICRP, 2009)].
S-value (radiation-weighted) S w ( rT
rS
)
The equivalent dose in target tissue or organ rT per nuclear transformation of a
given radionuclide in source region rS, Sv (Bq s) -1 , for the Reference Adult
Male and Reference Adult Female.
ER,
i YR
, i (
rT
rS
, ER,
i )
S w(
rT
rS
) wR M ( r )
R i T
where:
ER,i is the energy of the i th radiation of type R with the unit joule (J),
YR,i is the yield of i th radiation of type R per nuclear transformation,
(Bq s) -1 ,
wR is the radiation weighting factor for radiation type R, Table 1,
(rT←rS,ER,i) is the absorbed fraction,
M(rT) is the mass of target tissue rT, kg.
Target Tissue (rT)
Tissue or organ of the body in which a radiation dose is received.
Tissue weighting factor, wT. See also ‘Effective Dose’.
The factor by which the equivalent dose in an organ or tissue T is weighted to
represent the relative contribution of that organ or tissue to overall radiation
detriment from stochastic effects (ICRP, 1991). It is defined such that
w T 1
T
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