GENERAL COMMEMTS
We can understand the concept of changing the settings of dose limit fromequivalent doses to absorbed doses to prevent tissue reaction. However, practicalguidance on how to actually use absorbed dose limit to avoid non-cancer effects
should be prepared until new main recommendations are issued. It has not beenclarified yet how we should use the absorbed dose including RBE, particularly forhigh-LET radiation. Pub. 118 did not provided updated knowledge on high-LET
radiation. For skin and extremities, wR can be used for absorbed dose limits for skinand extremities, because RBEM and RBEm have been compared. However, for thelens of the eye, such comparison has not been made, and RBE will thus be more
appropriate.

The summary of the October 2012 Main Commission meeting states “the use of thespecial name sievert without proper context can cause confusion, and therefore
recommends that the quantity (effective dose or equivalent dose) always bespecified. Furthermore, when used for equivalent dose the relevant organ must also
be specified”. This statement may be explicitly described in this report, i.e., notingthat “when used for absorbed dose the relevant organ must also be specified”.

This document is a supplementary guideline for the use of effective dose describedin Publ.103. So, ICRP should give us a possible scientific evidence for the items
mentioned in this document as a reference. For example, in this draft document
para. (46), it is mentioned that “for doses in excess of 100mSv delivered at high doserate, a DDREF of two applied in determining solid cancer risk at low dose /dose
rates will not apply”. ICRP should identify the value of high dose rate above whicha DDREF of two is not applicable to evaluate radiation risk at an actual field while
showing the scientific evidence.

According to the report of TG84 they mentioned that the lack of a formal quantity
for a radiation-weighted dose for high doses was an issue in the current radiologicalprotection system. We think that ICRP should add the comment to this issue in thisdraft document.

SPECIFIC COMMENTS
Main Points lines 241-242
Section 3.7 (63)As described in this draft document (63) the use of committed doses introduces
conservatism into calculation of doses from annual intakes for the radionuclide
with long half-lives and long retention time, which should be reconsidered to avoid
irrational anxiety or excess concern about internal exposure among the public andworkers.
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Main Points lines 221-223
Section 6 (126) line 2020-2022“its use exceptionally in emergency exposure situations at acute doses in the range
up to around 1 Sv (or the order of several 100 mSv) is reasonable”  For managing
short term exposure of the Fukushima emergency workers (age >40 with low risk
for radiogenic thyroid cancer), the equivalent dose to the thyroid was added toeffective dose (in the same way as for the planned exposure situation). There is thepossibility that this impeded emergency responses or led emergency workers toincrease their anxiety. As such, for management of dose to emergency workers,other index may be considered, taking into account mortality, lethality or severity ofhealth effects.
Section 6 (122) lines 1963-1973
ICRP is required to clarify the following points in advance. In updating the doselimit associated with non-cancer effects, ICRP should consider the establishment ofa factor substituting the radiation weighting factor so that radiation risks can beeasily evaluated even in a mixed radiation field.
・Concept of setting the dose limit (how are the effects of high LET radiation andthe distribution of tissue doses incorporated in setting the dose limit)
・Evaluation of doses associated with non-cancer effects (a specific way ofevaluating doses in the work place exposed to mixed low and high LETradiation)
Section 6 (126) lines 2025-2028
The paragraph(126) describes the thyroid tissue reaction; if there was a significant
contribution to the effective dose from radionuclides concentrated in particularorgans (e.g., iodine-131 in the thyroid, inhaled insoluble radionuclides in thelung),tissue damage could occur. Notable for 131I, for example, an effective dose of
250 mSv could correspond to a thyroid dose of >6 Gy. On the other hand, ICRP Publ.
41 notes that if the whole thyroid is exposed to approximately 25～30 Gy x-ray
doses in fractions for 30 days, it could result in serious functional damage. It isnecessary to clearly describe the effects that may be caused by the difference in thethyroid tissue reaction from Publ. 41 description.
Section 3.7 (64) lines 1209-1213

Dose coefficient for internal exposure due to radiopharmaceuticals has been
provided for age groups, but the control of public or occupational exposures does notinclude medical exposure. This statement may need to be added.
Section 4.2 (88) lines 1522-1524
“It is important to balance the reduction in doses with any deleterious effects of theaction and a cautious assessment of doses could lead to unnecessary actions withadverse consequences for the affected population.”  For optimization purposes, abalance between the degree of caution and efforts for dose reduction is important inany exposure situations. To clarify this, the following revision of the sentences is2

proposed. ”It is important to balance the reduction in doses with any effort orresource to reduce dose in any exposure situation. Particularly in an emergency
exposure situation, a too cautious assessment of doses could lead to unnecessary
actions with adverse consequences for the affected population.”

Section 5.4 Table 5.2
It needs to be explicitly stated that this table is only dedicated to risk
communications for medical exposures of adults. From the viewpoint of risk
communications, it is important to touch on epidemiological observability as wasdone in Table 1 of Publication 96. In the second column from the left, it needs to bestated that risk at <0.1, 0.1-1, 1-10 mSv is also based on LNT in addition to that at
10-100 mSv. The label for the second column from the right may be changed from
“Proposed term for dose level” to “Proposed term for dose level in medical exposureof adults”
Section 1 (3) lines 327-328
The need to define the concrete level of low dose rate is unclear, and it may bebetter if only the order of magnitude is described while describing the relevant
numbers: e.g., <5 mGy/h [originally defined by Wakeford & Tawn (PMID: 20234068)
and employed by NCRP], <6 mGy/h averaged over a few hours (defined byUNSCEAR 1993), and 0.1 mGy/min averaged over one hour (UNSCEAR 2012).
Section 1 (6) lines 368-370
“The use of equivalent dose in setting limits for the avoidance of tissue reactions in

the cases of irradiation of the hands and feet, lens of the eye, and skin; that is,limits set below thresholds for the occurrence of acute damage to organs andtissues.”  “acute” needs to be deleted. Take cataracts and circulatory effects for

instance: these thresholds are set for effects occurring at >20 years and >10 years
after exposure, respectively.

Section 1 (6) lines 370-372“In general, smaller differences in effects per Gy are observed between radiation
types in relation to tissue reactions than stochastic effects (ICRP, 2003b).”  This
does not apply to the lens because the lens does not develop tumors.
Section 2.2 (10) lines 440-443
“However, the available data indicate that differences between radiation types (e.g.

alpha particles and neutrons relative to gamma rays) in their effectiveness per Gy
in causing tissue reactions are smaller than differences in their effectiveness inrelation to cancer induction (ICRP, 1990, 2003b).”  This does not apply to the lensof the eye, because the lens does not develop tumors.

Section 5.1 (97)Dose conversion coefficient for effective dose due to external exposure and dosecoefficient for committed effective dose due to internal exposure should distinctively3

be described.
Section 5.4 (116) lines 1853-1854

“Depending on the risk projection models used, there are also differences betweenpopulations.”  Risk can differ among populations, but population transfer is used
for simplification.
Section 6 (122) lines 1970-1973
“This change to the use of absorbed dose rather than equivalent dose would not

require changes to the numerical values of dose limits for tissue reactions and will
be considered by the Commission when new general recommendations areformulated.”  It is unclear what the Commission will consider upon formulation of

the new general recommendations.

Section 6 (125) lines 1997-2000
“It has been argued that this approach does not adequately protect women andyounger children and that differences between males and females and greater risks
at younger ages should be reflected more explicitly in the ICRP system, including
the use of different detriment values and wT values.”  Detriment is used only forderiving wT. As such, age-, sex-dependent detriments have no specific functions inthe system of radiological protection as indicated in Table A.4.18 of Publication 103.

Section 6 (126) lines 2028-2033
“A secondary consideration is that for doses in excess of 100 mSv (or more precisely,absorbed doses to organs and tissues > 100 mGy) delivered at high dose rate, theDDREF of 2 applied in determining solid cancer risk at low doses will not apply, sothat risks may be somewhat greater than might be assumed on the basis ofPublication 103 (ICRP, 2007a) nominal risk coefficients.” The risk posed by acuteexposure to >100 mSv can directly be estimated based on epidemiological evidence,
rather than with the nominal risk coefficients.

EDITORIAL COMMENTS
Section 2.6 (21) lines 687-688
“Risk of Exposure-Induced InCidence (REIC)” may be changed to “Risk ofExposure-Induced Cancer”
Section 3.2 (34) line 841
"clinical radiology” may be changed to “radiology, radiation oncology”.
Section 3.5 Fig 3.2
"reference phantoms” in the title may be changed to “adult reference phantoms”.
Section 3.6 (54) lines 1085-1087
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“The standard approach to the calculation of skin doses is to determine the average
dose to the most exposed 1 cm2 at a depth of 70 μm (ICRP, 1991a, 2007a)”  The
local skin dose is defined by the mean equivalent dose in 0.07 mm depth averaged
over any 1 cm2 of the skin, regardless of the area exposed.

Section 3.7 (58) lines 1143-1147
“the increased importance of the lens of the eye with the reduction in the dose limit

to 20 mSv per year (ICRP, 2012a) has led to a re-evaluation of its application (ICRP,2010a; Bolch et al., 2015).”  “20 mSv per year” may be changed to “20 mSv/year
year, averaged over defined periods of 5 years, with no single year exceeding 50
mSv”.

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