Dosimetric quantities

Draft document: Dosimetric quantities
Submitted by Dietrich Harder, Medizinische Physik Und Biophysik
Commenting as an individual

Dear collegues, in my understanding of the never-ceasing obligations as a former member of the ICRU and former chairman and member of the German Radiation Protection Commission I want to submit some proposals for amendment of the above specified draft of the chapter “Basis for dosimetric quantities used in radiological protection”; task group chairman Christian Streffer. Let me first say that I am quite happy about the general quality of the draft and not at least about the fact that some recent recommendations of the German Radiation Protection Commission, e.g. on the radiation weighting factor for neutrons, have been adopted. However, I have some proposals for improvement, and I am interested in the correct presentation of the considerations contributed by SSK 2004 within the framework of respectable efforts for a fair synthesis of the independent contributions by ICRP 2003a and SSK 2004. Page 20, line 24: Delete “at low doses”, because this qualifier is not needed at this place, and put in a comma instead. Page 25, line 10: Clearer arrangement of the sentence: “For incident neutrons, the radiation quality inside the human body is strongly dependent…” Page 25, line 12: “following” Page 25, line 14/15: Replace “at low neutron energies” by “which increases with decreasing neutron energy” Page 25, line 36: Behind “animal data” please insert “for carcinogenesis and life shortening” in order to characterize the kind of data. Page 25, line 37: Before “It is…” please insert the following sentence: “The same conclusion has been drawn by SSK (2004)”. It would be appropriate to account for the thorough treatment of animal data which independently lead the SSK to recommend the value 20. Page 25, line 44/45: Replace “low-energy neutrons” by “fission neutrons or low-energy neutrons”, because the appearance of the secondary photons is not confined to low energies. Page 26, line 16: Insert “factor” after “weighting”. Page 26, line 18: Delete “and then” and start new sentence. Page 27, line 8: Replace “low energy range” by “range below about 1MeV”. Page 27, line 13: In order to substantiate the important statement “independent on energy”, it is necessary to quote at this place the extensive chromosome aberration work by “EDW 97, SA 92, SCH 03)”. These three papers are: Edwards, A. A. The use of chromosomal aberrations in human lymphocytes for biological dosimetry. Radiat. Res. 148 (suppl.) (1997) 39 - 44 Sasaki, M.S., Saigusa, S., Kimura, I., Kobayashi, T., Ikushima T., Kobayashi, K., Saito, I., Sagusa, N. Oka, Y., Kondo, S. Biological effectiveness of fission neutrons: energy dependency and its implication for the risk assessment. In: Proc. Internat. Conf. on Radiation Effects and Protection. Mito,Japan (1992) 31-35 Schmid, E., Schlegel, D., Guldbakke, S., Kapsch, R.-P., Regulla, D. RBE of nearly monoenergetic neutrons at energies of 36 keV – 14.6 MeV for induction of dicentrics in human lymphocytes. Radiat. Environm. Biophys. 42 (2003) 87 - 94 Page 27, lines 28/29: The chosen value RBEhigh-LET = 25 has nothing to do with the induction of dicentrics (EDW 97, SAS 92, SCH 03); in fact for chromosome aberrations RBE values up to 80 have been found with Co-60 gamma radiation as the reference! Rather, at this place of the text, the work of SSK is being reported which was entirely based on animal RBE data for tumor induction and life shortening. Therefore lines 28/29 should read: “… component a value of RBEhigh-LET = 25 is chosen which is consistent with experimental animal data for tumor induction and life shortening (SSK 2004, Dietze 2004).” Then continue “These selected RBE-values result in an…” Page 27, line 34: “…up to 1 MeV neutrons and was approximated by equ. (4.6)”. It would be appropriate to mention that equ. (4.6) has been proposed in SSK 2004. Page 28, line 1: “is” Page 28, lines 4 and 3 from below: It would be appropriate to mention that the maximum value 20 was independently proposed by SSK 2004. Therefore the sentence should end with “…and SSK (2004).” Page 28, lines 1 and 2 from below: It would be appropriate to mention that SSK 2004 has independently proposed energy-dependent wR values. Therefore lines 2 and 1 from below should end with: “ …and SSK (2004).” Page 29, lines 1 and 2: This is not the full story, because the general shape of the curve was as well based on the independent considerations of SSK expressed in the “mixing rule” equ. (4.5), and the resulting curve shape has been proposed by the SSK in the form of equ. (4.6). Within a fair compromise, the sentence could be formulated as “The general shape of the curve for the energy dependence of wR was based on the energy dependence of the mean quality factor qE as well as on the “mixing rule” expressed in equ. (4.5).” I hope that these recommendations for amendment will be found useful. With kindest regards