HEMATOLOGIC OBSERVATIONS
dividuals have been possible, and thus they comprise the most complete data available on human
group I |
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NEUTROPHILES » iO”
FIGURE 4.8.—Cirmulative neutrophile counts for Group
I (Rongelap) at the time of imactanue depressions
and at 6 months after erposurc.
It is seen that in terms of absolute counts, the
children showed a greater depression of the
lymphocyte count. Expressed as percent of
control], all elements were affected more markedly in the younger age group. These results
would indicate that children are more sensitive
to radiation, or that other biological or physi-
sal factors resulted in a relatively greatereifect.
One physical consideration that may have accounted in part for the apparently greater dose
received by the children involves a consideration of dose distribution in the body. Because
of their relatively small diameter, the dose received at the center of the body of a child would
be greater than for an adult exposed to the
same dose as measured free inair.
4.4
4.41
55
Discussion
General
An estimation of the severity of radiation
damage incurred can be attempted by comparing the present results with previous hematological data on total body exposure. The
present data represent the only large series in
which systematic serial counts on the samein-
beings exposed in the high sublethal range. It
is also of importance, therefore, to examine the
present results in conjunction with past experience in an effort to gain a better understanding
of the hematological response of human beings
exposed to penetrating radiation in the sublethal range.
In the following discussion it will be gener-
ally assumed that the hematological effects
noted were due primarily to the penetrating
gammaradiation received. The beta radiation
injury of the skin may have contributed to
fluctuations in the white count during the period of active lesions during the third, fourth
and fifth week, but is considered not to have
contributed significantly to depression of any
peripheral.elements (Chapter 3). The degree
of internal contamination withfission products
(Chapter 5) was probably too small to contribute significantly to the early hematological
effects observed. Although it is not possible
to say with certainty that these added factors
did not materially affect the hematological pattern seen, it will become evident in the discussion that the changes observed are not inconsistent with those to be expected from exposure
to penetrating radiation alone. Thus, the
hematological changes noted are considered to
be the result of a single exposure to penetrating
gamma radiation, delivered at a rapidly decreasing dose rate over a period of approximately 2 days. Unless otherwise stated all discussion will be limited to the older-age subdivision of Group I.
The principal sources of previous data available for comparison, and the characteristics and
limitations of each are summarized in Table
4.10. Perusal of the table will make apparent
the difficulties involved in attempting strict
comparisons; however, some statements can be
made despite the obvious limitations. For
easy reference, “normal” values for peripheral
blood counts, from the present data and from
the literature are presented in Table 4.11.