ciency will be discussed under paragraphs 192-213.
Once more, it should be
pointed out that there is no fundamental biophysical reason why the shape of
the neutron curve should be of the form roughly described by the above equations, because the same observations pointed out for the x- and gamma-ray data
under paragraph 93 would be expected to apply to the neutrons as well.
How-
ever, the form of the neutron relationship is curvilinear (convex upward) within a range of effect where a linear function applies to low-LET relationships.
Since saturation phenomena with respect to the expression of the biological
damage might not be expected under such conditions, the only way to interpret
the neutron data is by assuming that the shape of the relationship does reflect some primary biophysical difference in the mode of action of low- and
high-LET radiation, particularly at the low doses.
96.
The effects of single acute exposures of low-LET radiation on animals
other than the mouse are summarized in Figure IV, in comparison with all the
mouse data.
At inspection, no large differences may be traced from the small
series reported in the literature.
This is particularly true for the rat,
whose data are well superimposable up to 500 rad with the mouse response.
The
response of the dog has only been examined at relatively low doses and the data
are perhaps on the high side of the mouse data.
The chinese hamster, on the
contrary, has only been examined at doses in excess of 500 rad and the data are
suggestive of a concave upward trend.
Between the species tested, however, the
variability of the response is apparently rather small.
B.
OT.
THE EFFECT OF CONTINUOUS LIFE-TIME IRRADIATION
The "duration-of-life" exposure condition has been used since the very
beginning and is documented in the early papers of Henshaw [H1], Evans [E2],
Lorenz et al. [L6] and Boche [B11].
It has widely been utilized in the ex-
perimental series of Sacher and Grahn [S4] who have largely contributed to
the interpretation of this type of data and is still in use at present [N6, NT].
In this case of internal irradiation from radionuclides of long half-life it
is naturally the only possible irradiation condition.
Exposure for the entire
life represents a base-line condition of irradiation useful for comparison
with other exposure types like the acute single-dose:
in respect to this lat-
ter it has the advantage of mimicking a pattern of exposure which is the most
interesting in practice, since the continuous chronic rather than the short
i