Appendix 2B Weighting Factors for Organs and Tissues

DOE-STD-1098-99

Radiological Control

Radiological Standards

March 2005

Appendix 2B

Weighting Factors for Organs and Tissues

[see 835.2(b), Weighting factor]

WEIGHTING

ORGANS OR TISSUES

FACTOR

Gonads .................................................

0.25

Breasts .................................................

0.15

Red bone marrow.................................

0.12

Lungs ...................................................

0.12

Thyroid ................................................

0.03

Bone surfaces.......................................

0.03

Remainder............................................

0.30

Whole Body ........................................

1.00

Notes:

Weighting factors as defined in ICRP Publication 26 and NCRP Report 91 are used to convert organ or tissue dose equivalent to effective dose

equivalent for the whole body. The effective dose equivalent is obtained by multiplying the organ dose by the weighting factor. For example, a

5 rem dose to the thyroid would be multiplied by the weighting factor 0.03 to yield a contribution of 0.15 rem to the total effective dose

equivalent.

"Remainder" means the five other organs or tissues with the highest dose (e.g. liver, kidney, spleen, thymus, adrenal, pancreas, stomach, small

intestine, and upper large intestine). The weighting factor of 0.30 results from 0.06 for each of the five remainder organs [see 835.2(b),

Weighting factor, Note 1].

For the case of uniform external irradiation of the whole body, a weighting factor equal to 1 may be used in the determination of the effective

dose equivalent [see 835.2(b), Weighting factor, Note 2].

2-19