a) I absolutely agree to the proposal.
b) It is also necessary to discontinue smaller (a tenth) dose limits of the lens of eye and skin for members of the public compared to occupational workers, since these dose limits are set for protection against tissue reactions.
a) I strongly disagree with the idea of expressing medical exposures by using effective dose, since it is useless either for justification or optimisation of radiological practices and will bring an excessive burden of explanation to clinicians.
b) The GOOD for patients in the medical use of radiation is to deal with the clear and present health problem that evidently overwhelm the HARM of radiation exposure that might occur in far future. Therefore, expressing medical exposures by the effective dose is not helpful for the justification of the medical use of radiation.
c) When the dose distribution in the body varies, the information obtained from detected radiation is not the same. It would be an unjustifiably overconfident and extreme position to attempt to optimise radiological practices only by comparing the effective doses, while the clinical information obtained from different modalities or techniques are not the same.
d) The draft proposes to record history of medical exposures of each patient using effective doses. However, the appropriate X-ray exposures as well as proper quality of radio-pharmaceuticals for the same medical examination vary with the physique, physical constitution and morbid state of the patient. Therefore, the history of patient’s medical effective dose is not helpful for decisions following radiological practice.
e) The draft proposes to record the effective doses of patients in the case of unintended exposures and overexposures. The effective dose, however, excessively truncates information of the incident. It is necessary to record precise information of radiation exposure to reconstruct the incident for studying prevention of the recurrence.
a) I think this is a wrong idea for the use of effective dose since it requires an excessively laborious explanation regarding the background of the concept of effective dose and of stochastic effects of low dose radiation to prevent misunderstanding.
b) It should be noted that the statements such as shown in paragraph 157 of the ICRP 2007 Recommendations are based on the painful reflection on the spread of the inappropriate use of effective dose for risk estimation. The proposal is contrary to the established wisdom.
c) Although cautions on the interpretation of “possible health risk” assessed by effective dose are repeatedly shown in the draft, it is not easy to explain this caution to non-professionals up to insure understanding. Especially, it is a burdensome request to clinicians to explain it in daily radiological practices.
a) I propose to discontinue this illogical procedure.
b) Although annual effective dose from external exposure and annual committed effective dose from internal exposure are expressed using the same unit (Sv/a), they are different quantities. While the value of the former is fixed, that of the latter is nothing but the prediction of a dose to be received within 50 (or 70) years from intake of radionuclides in the year. Therefore, the latter largely overestimate the dose received in a year for radionuclides with long half-lives as Gonzalez pointed out. Moreover, the actual dose can be further reduced when excretion of the radionuclide is promoted by administering chelating agent,
c) Effective dose is exclusively defined in the ICRP 2007 Recommendations as the gender averaged value of doubly weighted average of tissue and organ absorbed dose throughout the body of standard adult Caucasian, the Reference Person. The effective dose from external exposure follows this definition, while the committed effective dose is assessed for various ages and each gender considering age- and gender-dependent physique and metabolism, which does not harmonise with the definition of effective dose.
d) In the usual radiation protection practices, external exposure is controlled by effective doses (as well as its approximations, operational quantities) with the annual effective dose limit and relating dose constraints, while internal exposure is controlled by amount of intakes with the annual limit of intake (ALI) and relating constraints. Each control procedure is completely independent and both annual effective dose limit and ALI have large safety margin. Therefore, there is no rational reason for converting the amount of intake to annual committed effective dose.
e) By discontinuing the illogical habit of totalling external and internal dose by using effective dose, the inconsistency of age- and gender-dependent committed effective dose also defined as effective dose will disappear (at least superficially). It should be noted that this proposal will not bring any actual changes in radiation protection practices except for eliminating useless conversion calculation of committed effective dose.