38 EFFECTS OF IONIZING RADIATION and the severe, spotty epidermal injury with minimal dermal injury are notable. The particulate nature and uneven distribution of the fallout material was responsible for the spotty nature of the lesions and, the large componen: of soft energy beta radiation was responsible for the greater epidermal injury. The prominence of pigmentary changes is probably re"lated to race.* It is generally conceded that blondes with light pigment are more sensitive to radiation than brunettes (17). Lastly it is quite evident that sensitivity and response varied with anatomic location. In Table 3.3 are listed the approximate sur- face skin doses required to produce recognizable epidermal injury from beta radiations in ani- in comparing animallesions from known do with lesions in the exposed individuals in t study in order to estimate the skin dose, sil species differences in response may exist, 3 certain radiation factors are not well est lished, sych as accurate knowledge of the b spectrum of the fallout material and dose r: Comparison with human data sutfers from w differences in radiation energy and doses ported und methods of determining the | dose. The low incidence of infection of the rad tion burns is probably due to their superfic nature. Ulceration and partial healing r ceded the time of minimal granulocyte cout It is conceivable, however, that with hig Table 3.3.—Surface Doses Required to Produce Recognizeable Epidermal Injury INVESTIGATOR | ANIMAL | : 1 Raper and Barnes (23) _._.. - | Raper and Barnes (23)......| Snider and Raper(24)... ._- | Raper and Barnes (23)....... Rata......... Mice........- i Mige......-.., Rabbits. __ ; IsotorE | 1 AVERAGE ENRgROY | (Mav) | | Henshaw,et al (22)... _..-- | Rate... | P= = 0.5 Lushbaugh (28)... -..-...- | Sheep... .... ; Sf | 03 Moritz and Henriques (26)_.| Pigs.........| Co Moritz and Henriques (26)... Piga_._..__.. Moritz and Hennques (26). ‘| Pigs...___..- Moritz and Henriques (26)__| Pigs._____..- ' Moritz and Henriques (26)... Pigs..._._... , Morita and Henriques (26). | Pigs...___.- | | mals. It is apparent from the table that beta ray energy is of considerable importance in de- termining the degree of injury. According to Moritz and Henriques, the difference in dose between that required to produce threshold skin damage and that for permanent damage in pigs is 500 to 1000 rep (26). One is not justified * Reported clinical experience with radiation skin lesions is based predominantly on the response of white-skinned people, whereas the lesiona described herein were observed primurily in the Marshallese, a highly pigmented people. P™ pe P® Pw Se ' | © | 0.05 © 0.01 ' | O38 O5 Ca | oye | Sree ¥t 65 @s OS O65 | 1, 800-4, 000 4,000 2, 500 2, 500 5, 000 2, 500-5, 000 — 0.2 0.7 Scrrace Doag (xP) 20, 000-30, 000 4, 000-5, 000 2, 000-3, 000 | ! 1, 500-2, 000 L, 500-2, 000 1,500-2, 000 doses of whole-body radiation, the defen against infection might have been sufficier impuired to have resulted in serious compli tions from skin lesions of the severity enco tered. Severe radiation injury is known to pre pose to cuncer. The probability of the devel ment of malignancies at the site of healed sions is unknown. Certain factors appear decrense the probubility: (a) The majority the lesions were superticial. (b) Visible si of chronic radiation dermatitis are absent