The ICRP Computational Framework for Internal Dose Assessment for Reference Workers: Specific Absorbed Fractions


Draft document: The ICRP Computational Framework for Internal Dose Assessment for Reference Workers: Specific Absorbed Fractions
Submitted by Fumiaki Takahashi, Japan Atomic Energy Agency
Commenting as an individual

Paragraph 11
P. 19 Lines 548-550
Values of the target region fractional weights are taken to be “the fractional masses of stem cell layers” in Publication 100 for colon. However, the mass faction of alimentary tract walls is taken into account to derive the equivalent dose for colon at paragraph (264) in Publication 100. The equivalent dose is based upon the averaged dose over a tissue or an organ. Thus, it may be considered that definition in ICRP 100 is correct for calculation of equivalent dose.

P.19 Table 3
The values of fractional weights for colon in Table 3 do not strictly correspond to the factional masses of the stem cell layers in Table 7.8 in Publication 100 or the colon in Publication 110. Some explanation should be added in the text of Publication for SAF 

Paragraph 21
P.24 Line 674
There is no data for the masses of organ or tissues in Annex D of Publication 110. I guess that “Annex A” is correct.

P.24 Line 682 (also Annex A)
At paragraph (49) in Publication 110, two formulae (1 and 2) are given to derive material data of liver in the ICRP reference phantom with a consideration for fraction of involved blood. Here, the masses of “liver minus blood” and “blood in liver” are   multiplied by the fraction of hydrogen for “liver” and “blood” in ICRU Report 46, respectively. And then, the sum of the multiplied values is divided by the mass of “whole liver”. If we calculate the mass fraction for each element with these formulae, the result corresponds to the value in Tables B.1 and B.2 (Annex B) in Publication 110. Thus, it can be assumed that content of blood is taken into account for material data for organs and tissues in the ICRP reference phantom of Publication 110.

The masses of source region in Table A.2 of the draft correspond to the data in Table A.1 of Publication 110 (Annex A). The masses of blood may be added to the masses of source region in Table A.2 of to derive the masses of target tissues in Table A.1 of the draft. The data in Table A.1 of Publication 110 (Annex A) correspond to the masses of organs and tissues for the reference persons in Publication 89. So, I guess that double-count of blood is made to derive the masses of target tissues in Table A.1 of the draft.

Paragraph 40
P.35 Table 4
The values of “Bone” in Table 4 of the draft are about 2/3 of the data in the CD attached to Publication 100. The new publication for SAF should give the explanation for these differences or some other references, if ICRP revises the mass ratios of “Bone”.

Paragraph 44
P.37 Table 6
T
he data for “spongiosa” and “lymph” in Table 6 do not correspond to the data in the CD attached to Publication 100. The new publication for SAF should give the explanation for these differences or some other references, if ICRP revises the mass fractions for “spongiosa” and “lymph”.














Back