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RADIATION STANDARDS, INCLUDING FALLOUT
have cooperated closely. The overall problem is extraordinarily complex and neither group has reached any definite conclusions. I will
be surprised if they do within the next few years, but I think it is
safe to predict that some new‘and important concept will result from
their studies.
"
The ICRU which met in Switzerland last spring was asked to de-
fine the RBE dose concept in consonance with the'other physical definitions of radiation quantities andunits. Its tentative recommendation embodying absorbed dose, a risk concept and judgment factors
was not accepted by the ICRP as such, although the general principles were. In the meantime we will continue to use the present
“RBE dose” concept.
The problem of dose additivity becomes even more complicated when
you attempt to combine as a single risk factors a dose to, say, the
thyroid from I-131 and a dose to the hands from an external source,
say, X-rays. The NCRPis considering a radically newapproach to
the problems but it is too soon to say whether the end product will be
useful.
,
Additivity of doses is of principal importance to radiation workers
in the atomic energy field. Under present conditions it is mainly of
academic interest with regard to population exposure, since these doses
are so very low in thefirst place.
In spite of the generally low exposure of the general population,
efforts continue to either hold the line or reduce it further. Exposure
of children has long been recognized as a limiting benchmark in dealing with population groups and the FRC hasrecently specified this
clearly in its Report No.2.
The possibility of undesirable radiation exposure of students and
staff in schools in the course of either experiments or demonstrations,
has been recognized. Early this year the NCRP established a subcommittee jointly with the American Association of Physics Teachers and the PHSto study the problem. At its May meeting the ICRP
also decided to study the question. An initial survey has indicated
that while the problem does not appear to be critical in the United
States at present, it might in the future. We will try to forestall the
possibility without introducing unnecessary restrictions in the instructional uses of radiation sources.
.
The matter of relatively large accidental exposures of radiation
workers is still a matter of concern, more from the administrative
than the biomedical point of view unless the overexposures are very
large. At present, any exposures beyond the prescribed MIP’D ten.t
to be viewed with administrative alarm in spite of the fact that the
effects of say 25 rems are essentially undetectable in the individual.
Nevertheless, accidents will occur with the worker possibly penalized
as to his future work potential. Both the NCRP and ICRPare actively studying this problem.
Exposure of the population to very large doses of radiation, such
as may be expected in the event of a nuclear attack or a major nuclear disaster, presents an entirely different order of problem. This
has been under study by the NCRP for some 7 years and a report
on the subject was issned a few months ago. Some of the recommendations regarding disaster decisions sound very harsh, as indeed
they are. On the other hand, they are based on the philosophythat
Pnetittineis
Cabseeabe
Sey “aes x
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