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Submitted by K. Manabe, JAEA
   Commenting as an individual
Document The ICRP Computational Framework for Internal Dose Assessment for Reference Workers: Specific Absorbed Fractions
 

I have some comments and questions.


Pages 19–20, lines 550–553, paragraph 11, “For the lymphatic nodes, 551 values of f(rT, T) are taken to be the fractional masses of lymphatic nodes (not lymphatic tissues) within the extrathoracic, thoracic, and non-respiratory regions consistent with data given in Publication 66 (ICRP, 1994).”


Both masses of LNET and LNTH are 15 g described in Table 24 of Publication 66, but I cannot find the mass of the lymphatic nodes within non-respiratory regions. Where can we find this information?


 


Page 24, lines 673–675, paragraph 21, “Small differences exist in the masses of the target tissues in the computational phantom (given in Annex D of Publication 110) and the masses given in Table A.1 of this report, as the latter includes the blood content of the target tissue.”


This sentence means the masses of organs and tissues indicated in Publication 110 do not contain blood. Is this right?


 


Page 24, lines 683–685, paragraph 22, “Self-irradiation SAFs for all radiation types were calculated by taking the self-irradiation AFs from the computational phantoms and dividing by the target mass given in Table A.1 of this report.”


I think this method can underestimate absorbed doses especially in small organs.



Page 25, lines 734–736, “A variance reduction technique called ‘bremsstrahlung splitting’ was employed to decrease the relative statistical uncertainty in the dose conversion coefficients of internal organs (Kawrakow et al., 2009).


I think the necessity for using a variance reduction technique is low considering performance of recent computers. And, how low is the target level of statistical uncertainty for SAFs?


 


Pages 26, 27, 29 and 30, Fig. 2, 3, 5 and 6


How the data at 1 keV of Fig. 2, 3, 5, and 6 were evaluated? Limiting SAF values are introduced in Annex B.5. If the data at 1 keV were evaluated by interpolation using data at 10 keV and limiting SAF values, the sentence at page 24, line 709, should be changed from “via extrapolation” to “via interpolation”. If the data at 1 keV were evaluated by extrapolation, data used in extrapolation and the method should be clearly described.


 


 Pages 57–58, Annex B.5


 The former handling of SAFs was very simplified for radiations below 10 keV. It is reasonable to introduce limiting SAF values, and to interpolate SAFs below 10 keV by data for 10 keV and limiting SAF values. However, interpolation method may affect the interpolated values. Which method is applied to interpolation in ICRP?