Blood Volume Changes in Carbon Arc Irradiation. ∗

Abstract

In previous communications^1,2,3 evidence was reported suggesting an increase in blood volume following carbon arc irradiation, which dilution was believed to mask actual increases in the physical and chemical blood constituents. In the present study we sought to determine the nature and extent of these changes in plasma and red cell volume.

Five short-haired, white dogs were irradiated abdominally with the “Pan Ray” carbon arc with dosages of 70 to 83 g. cal. per sq. cm. at intervals varying from 3 hours to 6 days for a total of 15 separate exposures. Total plasma volume was obtained by the dye method, using brilliant vital red; specific gravity by the falling drop method of Barbour and Hamilton; Hb by the Newcomer method and hematocrit according to Van Allen. Total cell volume was calculated indirectly from the hematocrit reading. The results, with minor exceptions, are uniform and confirm the previous evidence that the primary result of irradiation is an increase in plasma volume of 6 to 37%, depending on the dosage and the interval between successive exposures. The dilution usually reaches a maximum in each animal which is maintained but not exceeded by subsequent irradiation, except when massive exposures are given.