The Use of Effective Dose as a Radiological Protection Quantity

L 660 : wt coefficients are rounded to be pooled in three categories. For thyroid, this step introduces a factor 2. This “round off” step should be mentioned inter alia to support the fact that effective dose is not a relevant quantity to assess individual risk

Tables 2.4 and 2.5 : The baseline risk varies from a group of population to another (asians and euro-americans). For the risk excess due to radiation exposure, does ICRP assume that it doesn’t depend upon the group of population ?

Eng : L 933 : About equivalent doses, the document underlines that the unit assigned to this quantity (Sv) is confusing because this quantity is associated to the management of deterministic effects. I fully agree. Beyond, this remark questions the relevance to set different limits for the public and for workers for the skin, extremities and lens of the eye.

Eng : par 3.8 : about collective dose, I support the cautious use advocated by ICRP. The ICRP document may refer to the UNSCEAR document “ATTRIBUTING HEALTH EFFECTS TO IONIZING RADIATION EXPOSURE AND INFERRING RISKS” which mentions “the Scientific Committee does not recommend multiplying very low doses by large numbers of individuals to estimate numbers of radiation-induced health effects within a population exposed to incremental doses at levels equivalent to or lower than normal natural background levels”. In other words, it’s not recommended to use collective dose for individual incremental doses lower than few millisieverts. Nevertheless, it should be noted that multicriteria methods more and more resort to collective doses and risk inferred from collective doses (DALY, euros or dollars for example) to weigh different options (life cycle impact assessment). I think that the ICRP can’t fully ignore these tools and in the meantime to promote an integrated approach of radiological protection.

L 1418 : the effective dose is a quantity which shall be handled very cautiously when used to appraise the exposure to natural radioactivity in existing exposure situations. The document should remind that effective dose is linked to an risk excess. Thus all exposures to natural radioactivity musn’t be systematically accounted to figure out the effective dose (eg ⁴⁰K in the body)

Eng : par 88 and 89 : it would be more logical to swap these 2 paragraphs. First, ICRP indicates that underestimations should be avoided when no data are available. This cautious approach shall be kept in mind to balance the effects of exposures and the adversed consequences of actions when required.

L 1604 : Practionners could be added to the list

L 1790 : The section 5 on medical exposures contents a chapter dedicated to risk communication. It would be useful and informative to add the same chapter in section 4, especially for public exposure.

L 1914 : the same figure than fig 5.1 may be added for euro-american population.

Summary and conclusions

L 2055 : the text should be clearer about the fact that effective dose wasn’t designed to assess the individual risk due to the exposure of one organ.

L 2080 : the age and sex dependence of risk for a same exposure is also applicable to the public. It is important to mention that this sensitivity should be taken into account especially in emergency situations.

As the effective dose is widely used (eg : the pie for global average exposure), it would be useful to remind that effective dose was designed to reflect a risk excess. So it could be not appropriate to include all exposures into calculations of effective dose, especially for existing exposure situations.

The conclusion should also address the use of collective effective dose in life cycle impact assessment tools with a view to aggregating different midpoints related to human health. Good or bad practice ?