Dear Sir: I have a comment on radiation weighting factor for high energy particles which is mentioned in section 4.1 (p.28-30) in the ducument. I have analyzed the dose-LET distribution in human body irradiated by high energy neutron, proton and pions with energies up to 200 GeV. The results indicates that the contribution of lower LET charged particles generally becomes larger with an increase of incident energy, i.e; our results are similar to the those obtained by Pelliccioni (1998, 2004) and Yoshizawa et al. (1998) refered in the document. Hence, please refer the following paper as well as the above mentioned two papers in the document. Tatsuhiko SATO, Shuichi TSUDA, Yukio SAKAMOTO, Yasuhiro YAMAGUCHI and Koji NIITA, gAnalysis of Dose-LET Distribution in the Human Body Irradiated by High Energy Hadronsh, Radiat. Prot. Dosim. 106(2), 145-153 (2003) I have also analyzd the dose-LET distribution for high energy heavy ion irradiation cases. We found that the maximum values of the mean quality factors for each heavy ion are approximately 20, The result can support the decision of ICRP in terms of the radiation weighting factor for heavy ions; "The selection of a constant wR value of 20 for all types and energies of heavy charged particles is seen to be a rough estimate sufficient for the general application in radiological protection" (p.31 in the document) Hence, if possible, please mention our result in the section 4.1.6 with the following reference; Tatsuhiko Sato, Shuichi Tsuda, Yukio Sakamoto, Yasuhiro Yamaguchi and Koji Niita, gProfile of Energy Deposition in Human Body Irradiated by Heavy Ionsh, J. Nucl. Sci. Technol. Suppl. 4 287-290 (2004). If you cannot access the journal, I will send the copy of the paper. Best regards, Tatsuhiko Sato