HEMATOLOGIC OBSERVATIONS do dividuals have been possible, and thus they comprise the most complete data available on human beings exposed in the high sublethal range. It 109 90 is also of importance, therefore, to examine the 40 8 present results in conjunction with past expertence 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 generally assumed that the hematological effects noted were due primarily to the penetrating 8 QUMULATIVE PER CENT , d JK , ae ° a ( 2 pal a | on 3.064 1 i 1 $s 68 tT L $8 g$ L i909 tt gammaradiation received. 1 i2 ( ft NEUTROPHILES 510? Ficure 4.8.—Cumulative neutrophiie counts for Group I (Rongelap) at the time of mazimum depressions and at 6 months after cxzposure. It is seen that in terms of absolute counts, the children showed a greater depression of the lymphocyte count. Expressed as percent of contro], 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- cal factors resulted in a relatively greater effect. 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 smail 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 in air. 4.4 4.41 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 same in- 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 con- tribute 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 discus- sion that the changes observed are not inconsistent with those to be expected from exposure to penetrating radiation alone. Thus, the hematological changes neted are considered to be the result of a single exposure to penetrating gumma radiation, delivered at a rapidly decreasing dose rate over 2 period of approximutely 2 days. Unless otherwise stated all discussion will be limited to the older-age subdiviston 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 mude despite the obvious Jimitations. For ensy reference, “normal” values for pertpheral blood counts, from the present data and from the literature are presented in Table 4.11.