The Acute Radiation Syndrome

Abstract

The radiologist has had unique preparation for appreciation of the effects of acute radiation on the human organism. In meeting the challenge of increasing civilian and military uses of atomic energy, as well as the possibilities of atomic warfare, he must be concerned with the details of the acute radiation syndrome and new information concerning it. Until recently, the major sources from which such knowledge was derived were small animal experiments, clinical radiological experience, and reports of the effects of the Hiroshima and Nagasaki explosions. Estimations of the response of human beings to whole-body radiation as obtained by extrapolation from clinical experience have proved to be entirely inadequate. The very large volume of radiobiological data from small animal experiments is not completely satisfactory as a basis for predicting human reactions. The Hiroshima and Nagasaki observations are complicated by incompleteness of data on radiation intensities, lack of objective clinical studies in the early stages, and the presence of superimposed thermal and mechanical injuries. Two recent publications have such particular interest with respect to acute radiation reactions that it seems appropriate to direct specific attention to them. The acute radiation syndrome is described in papers of Hempelmann (1) and Hempelmann, Lisco, and Hoffman (2), based on nine cases of accidental exposure at the Los Alamos Scientific Laboratory. The second of these papers is a comprehensive monograph published as a separate part of the February 1952 issue of the Annals of Internal Medicine. In it, the acute radiation syndrome is defined as “the group of signs and symptoms which characterize the illness produced by exposure to ionizing radiations of the entire body or a large part of the body.” It is to the credit of the health and safety operations at the Los Alamos Laboratory that only ten such unfortunate accidents occurred. It is fortunate that these cases were so carefully studied. The radiations consisted of moderately fast neutrons and hard gamma rays from temporarily uncontrolled fission reactions. They did not produce uniform radiation patterns throughout the bodies of the exposed persons, but the patterns are carefully analyzed and the physical corrections seem adequate for comparison with homogeneous whole-body exposures. The individual cases are presented with clinical completeness, exhaustive documentation and analysis of laboratory data, and interpretation with regard to the biological basis for the clinical responses. In the ten cases from which the nine reported are drawn, two individuals died as a result of the acute radiation injury; one other showed a typical acute radiation syndrome and recovered. Four others, who received lesser exposures, showed hematological reactions. These cases are unique, they are presented with great care, and they merit the close study of all radiologists.