These signs reached the peak in about the 3rd- 4th week and subsided gradually. These skin lesions including epilation were observed on parts of the body not covered by clothing and on the navel region where radioactive dusts from neck were deposited. Histologically, these skins were similar to ordinary radiodermatitis. Remarkable epilation was observed in 20 patients. Two patients who did not wear hats at the time of the accident revealed complete epilational necrosis. Microscopically, coagulation necrosis and cell infiltration in the necrotic scalp was observed at about the 4th week. These skin lesions recovered gradually. Thin and delicate 3. Haematological Observations Leucocytes Total number of leucocytes decreased gradually, showing minimum count at about +8 weeks after the exposure. Five cases revealed a count of less than 2,000/mm’, thirteen less than 3,000, andfive less than 4,000. In one case, the leucocyte level depressed to 800. A correlation was found between these minimum count and the doses of individual external irradiation. Neutrophil level also depressed. Between the 4th-8th weeks all of the cases got minimum values, which were proportional to the dose of radiation received (Fig. 3). In most cases a shift hairs began to grow again at the beginning of May, and in 2-3 months they grew back almost completely. But, T-2 and T-7 have alopecia to the left of the nucleus was observed. Lymphopenia was noted between the 2nd-8th weeks in all cases. Leucocyte count began to increase since 8th observed in the navel region. elocytes appeared in peripheral blood of some even nuw. In somepersons, capillary dilatation, depigmentation and pigmentation ofskin arestill For the skin lesions every possible treatment was applied. For decontamination, mechanical washings with Na-EDT.A or warm water were done. The hair of head, axilla and pubes was shaved off. nails were cut off. The In one and half months superficial contamination was almost removed. The distribution of surface radioactivity and skin lesioris is shown in Fig. 2.'? week. At that time, metamyelocytes and mycases. In most cases eosinophilia and in some cases monocytosis were remarkable, especially with the indication of recovery. Eosinophilia con- tinued in some cases for several years without proof of parasite. Neutrophil and lymphocyte levels recovered gradually. However, cumulative distribution curve of total leucocyte count at the 6th year was still slightly displaced to the left of normal Japanese, and in several cases, number of lym- Radioactive Contominetion phocytes was below 2,000/mm’. Motility and phagocytosis of neutrophils de- pressed remarkably. Although they recovered gradually, after one year these functions in some cases were still lower than in normal persons. Erythrocytes At the time of hospitalization, a few patients were slightly anaemic (RBC 3,000,000/mm’). No reticulocyte was observed in them at the critical stage. The cumulative percentage curves chang- Marked “Uy Moderate Fig. 2, Mh Slight @e Uleer se Erosion th, te Erythema Epilation Distribution of Radiodermatitis'” ed as in Fig. 4. Colour index was higher than 1.0. The PriceJone’s curves of erythrocytes diameter were displaced to the right of normal one at first, and returned to almost normal after one year. These changes corresponded to changes of erythroblasts diameter in bone marrow.

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