The Use of Effective Dose as a Radiological Protection Quantity

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Section/Para/

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Comment

Proposed changes, if possible

General

1

Detriment and Uncertainties

Although the draft presents important information and guidelines on the use of effective dose as a radiation protection quantity, there are some subjects that make it difficult to gather understanding and guidance on recommendations. For example, the detriment calculation steps do not highlight differences (…”closely based’’…) from the method provided in the ICRP Publication 103, and the uncertainties for risk estimation do not describe a straight forward methodology.

Abstract

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107

5

Para

 It is not clear what the “specific aspects” are describing.

Suggest that specific aspects are defined …

3

  115

119-121

5

Para 

Para

This line seems to suggest that the effective dose is appropriate to approximate an individual’s risk. A stronger message or additional clarification would be required to deter the erroneous use of the effective dose. While the following lines (121-124) seem to try to address this, it still needs a stronger statement.

At minimum, it is suggested that the word “approximate” be changed to something that suggests the highly inaccurate nature of doing this (for example,. imprecise).

Main Points

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186 - 187

8

Para

The units of Gray and Sievert are not “special”.

Gray and Sieverts should be described as units.

5

188

8

Para

An absorbed dose is a physical quantity used for other purposes. The line suggests that absorbed is a radiation protection quantity. Please clarify.

Clarify the use of absorbed dose as a radiation protection quantity.

6

267-270

277-280

9

  10

Para

See comment # 3 above

7

281-285

10

Para

The statement “should be treated with caution” leaves it open to interpretation.

A clearer statement on “how” or “how not” to use the collective dose is suggested.

Introduction

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 311

 11

Para 2

 “Stochastic effects” is more appropriate than the term “biological effects” in order to harmonize terminology used throughout the document. This is the only instance where “biological effects” is used. “Stochastic effects” is used throughout the document.

Replace “biological effects” with “stochastic effects”.

Health Effects

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440 - 443

14

Para

“… differences between radiation types in their effectiveness per Gy in causing tissue reactions are smaller than differences in their effectiveness in relation to cancer induction (ICRP, 1990, 2003b)”. This may need to be updated since it was last updated 15 years ago and based on limited information. While this may not change the weighting factors, this limitation should be acknowledged.

Consider updating the statement described in the comment.  While this may not change the weighting factors, this limitation should be acknowledged.

10

686 - 687

20

 Para

It is not clear if the acronym, REIC (Risk of Exposure Induced Incidence) is correct. 

The acronym for REIC should be Risk of Exposure Induced Cancer.

11

21

Figure 2.1

The caption under the figure should be more descriptive to show that it is illustrating differences between cancer type, sex and age at exposure. Also it is not clear if the diagram is showing age of exposure; if this is the case, it should be clearer.

Review the caption under Figure 2.1 and revise ensure it adequately describes the figure.

12

22

Tables 2.4 and 2.5

To be consistent with Figure 2.1 (cases per 100 per Gy; %/Gy), organs should be in the same order for males and females to make comparisons easier. For females, female specific cancers can be added to the end.

The addition of (95% CI) would allow us to determine if there are any statistically significant differences between age at exposure and sex, and between the Euro-American composite population and Asian Composite population. 

13

23

Table 2.5

“Cases per 100 per Gy Power” requires a revision.

Delete “Power” from this sentence.

14

777

24

Para

“Radon-222 and daughters”

²²²Rn and its progeny (Progeny is used throughout document and daughters is used only once).

Use ²²²Rn for consistency

Introduce the terms progeny, decay products, daughters, explain they all mean the same thing, but pick one and use throughout the rest of document consistently.

15

778

24

Para

Plutonium-239 is written out here but ²³⁹Pu is used everywhere else in paragraph. Be consistent.

Use ²³⁹Pu for consistency.

16

820

25

 Para

Suggest deleting “It can be concluded that…”.

Revise sentence as “The available epidemiological data …”

Dosimetry

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1229

34

Para

Collective effective dose is not intended as a tool for epidemiological risk assessment. It should not be used in formal risk projections for such studies. In particular, the computation of cancer deaths based on collective effective doses involving trivial exposures to large populations is wrong and an inappropriate use of collective dose (ICRP, 2007a).

A stronger statement on the misuse of collective dose is recommended.

18

27

Figure 3.1

The text on Figure 3.1 is very difficult to read.

Please redraw Figure 3.1 so that the text is able to be read.

19

27 

Figure 3.1

The illustration of the energy function is very useful. However, its use may be challenging due to the quality of the illustration and/or missing of information.

It would be helpful if an adjusted mathematical energy function is provided to overcome these challenges.  

Occupational and Public Exposures

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 25

Section 3

Consideration should be made to add a subsection which discusses dose to the lens of the eye (as was done for skin dose). A consolidation of guidance for lens of the eye dosimetry would be beneficial for the global radiation protection community. 

Add a subsection to section 3 which consolidates all existing information in the draft publication on dosimetry for lens of the eye.

21

1147-1149

  33

Section 3.7 Para 58

It stated that:

In some situations in which individual monitoring is not carried out, an assessment of effective dose may be performed by area monitoring applying the quantity ambient dose equivalent (H*(10)).

ICRP should provide clarification and additional guidance on when the use of ambient dose equivalent (H*(10)) for assessing dose to the lens of the eye is acceptable/appropriate.

Provide clarification and additional guidance on when the use of ambient dose equivalent (H*(10)) for assessing dose to the lens of the eye is acceptable/appropriate.

22

1254

35

Para

An “s” is required at the end of “Exposure situation(s)”.

Add an “s” at the end of “situation”.

23

1272

35

Para

“It is important to note that …” is recommended to be deleted.

Revise the sentence as “Although effective dose is …”.

24

1278-1279

36

Para

It is recommended that “with respect to …” be deleted.

Revise the sentence as “”.

25

1348

37

Para

Radon-222 and their decay products.

It is recommended that “decay products” be replaced with “progeny”. As per comment #24, it is recommended that ²²²Rn be used for consistency.

Revise to “²²²Rn and its progeny”.

26

1411

38

 Para

Describe the misuse of using the collective dose (i.e., predicting deaths/cancers using collective dose multiplied by risk estimates.)

Provide a very clear statement on the misuse of collective dose for projecting the number of deaths/cancer resulting from very low doses in a large population. Discuss the uncertainties and assumptions made. Provide examples of the inappropriate use of collective dose to grossly overestimate the health impact of low dose radiation exposure (i.e., Ian Fairlie for Ontario Clean Air Alliance, 2018).

27

1440

39

Para

…dose as a function of age at exposure and…”.

“Sex” should be added to this sentence.

Add “sex” so that the sentence reads as follows: “…dose as a function of age at exposure and sex…”

28

1543

41

Para

For public exposures, collective effective doses can be used as part of the optimization process for planned, existing or emergency exposure situations (such as that used in UNSCEAR 2013 Report, Annex A, Levels and Effects of Radiation Exposure due to the Nuclear Accident…Table 8). The quantity also has a useful role in comparative studies to consider the radiological impact of different sources of exposure (i.e. Chernobyl vs Fukushima; CT vs x-ray).

Consider adding that for public exposures, collective effective doses can be used as part of the optimisation process for planned, existing or emergency exposure situations (such as that used in UNSCEAR 2013 Report, Annex A, Levels and Effects of Radiation Exposure due to the Nuclear Accident…Table 8). The quantity also has a useful role in comparative studies to consider the radiological impact of different sources of exposure (i.e. Chernobyl vs Fukushima; CT vs x-ray).

29

1523

41

Para

Provide examples, such as evacuation related deaths, radiation fear, stigma, etc.

30

1537

41

Para

In some instances, collective dose may be deliberately misused to grossly overestimate the health impact of low radiation doses. Itcan be a used for fear mongering; increasing public fear, stigma, and therefore resulting in unnecessary mental health issues to a population.

The misuse of collective dose is greatest in accidental situations (Chernobyl, Fukushima), but is also an issue with routine exposures around nuclear power plants.

Most members of the public do not know the difference between the right and wrong use of collective dose. It would be very useful for ICRP to discuss how collective dose has been misused and provide a much stronger message that it should not be used in these situations. It is based on too many assumptions and large uncertainties.

Consideration to avoid the use of collective dose and instead compare different representative persons, as in UNSCEAR 2013 should be made; this is far more accurate and less alarming an approach.

Provide a much stronger position here on the proper use of collective dose and highlight the misuse of collective dose

Collective effective dose is a valuable tool in the optimization of protection, particularly for occupational exposures. It is not intended for use in risk projection to predict potential/possible health effects.

Medical Exposures

31

1790

42

 Section 5.4 

This section could equally apply to section 4, Occupational and Public Exposures.

Provide a new section on Effective Dose and Risk Communication, and address the topics of education and training, communication of doses and associate health risks, age- and sex-specific cancer risks and effective dose for occupational, public and medical exposures. There is considerable overlap.

32

  43

Section 5 Para 96

Clarification is needed on the use of “effective risk” as a tool for characterizing medical exposure; especially when this is the only instance where “effective risk” is discussed in the publication.

Provide clarification on the use of “effective risk” as a tool for characterizing medical exposure.

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44

Table 5.1.

 Acronyms in the caption under the table should be defined.

Acronyms should be defined in caption under the table.

34

49

Table 5.2

UNSCEAR defines moderate as 100-1000 mSv and as high as 1000+ mSv

Add high doses and add a column of examples of occupational or public exposures to all the different effective dose levels. This table would be more valuable if not restricted to medical radiation procedures.

35

49

Table 5.2.

Replace 100s with >100.

36

1857

49

 Para

Along with referring to Section 2.6, Figure 2.1 should also be referred to.

Consider also referring to Figure 2.1

37

51

Tables 5.3 and 5.4

Total lifetime risk of cancer incidence (cases per 100) per Sv effective dose by (not as a function of) age at exposure and sex…

Is there a similar table based on epidemiological studies (i.e. LSS, occupational exposures, Chernobyl?)

If there is a similar table based on epidemiological studies (i.e. LSS, occupational exposures, Chernobyl), it should be added/included.

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51-52

Tables 5.3 and 5.4

Define acronyms in the captions under the tables.

Acronyms should be defined in captions under the tables (may want to add %/Sv for consistency).

Summary and Conclusions

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57

Paras

Collective Dose

See  comments #  17, 26 and 28

References

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  2171

58

Ref

Abbreviate the journal name

Change to: Radiat. Prot. Dosim.

41

  2206

59

 Ref

Check if article is still in preparation

Update information if article is no longer in preparation.

42

  2216

59

 Ref

Abbreviate the journal name

Med Phys

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  2317

61

 Ref

Abbreviate the journal name

Med Phys

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  2391

62

 Ref

Abbreviate the journal name

Am J Roentgenol

45

  2408

63

 Ref

Abbreviate the journal name

JAMA Intern Med

46

 2444

63

 Ref

Abbreviate the journal name

Radiat. Prot. Dosim.