Diagnosis of Acute Localized Irradiation Lesions

Abstract
In the last 50 years several radiation accidents occurred in which industrial radiographers and others suffered severe radiation injuries from inadvertent contact with radiation sources. Such accidents involving acute localized injuries are characterized by a severe initial reaction progressing through erythema to skin necrosis with a spontaneous resolution of the lesion over a 2-mo period for the lower doses. However, the early symptoms observed on the skin give no indication as to the in-depth pathology, and cutaneous and muscular radionecrosis started generally from early epithelia], microvascular, and vascular lesions and from delayed muscular and connective tissue lesions. In a case of acute localized irradiation, different biophysical techniques are able to give real responses in biological dosimetry. More numerous are the methods, especially imaging methods, that make it possible for the clinician to evaluate the extent of the early injuries and to manage the medical intervention. We have developed animal experimental models of acute localized irradiation: overexposure to the y rays of a 192Ir industiial radiographic collimated source (in the pig and the rabbit) and overexposure to the 13 rays of a 90Sr-90Y collimated source (in the pig). In these experimental models, most of the imaging techniques used in clinical practice, as infra-red thermography, microwave thermography, cutaneous and fissular vascular scintigraphy ((B) or (y) emitters), cutaneous blood flow measurements by cutaneous laser Doppler, × ray computed tomography, nuclear magnetic resonance imaging, and skin topography, were correlated with clinical evaluation and histopathological observations, after high doses of (y) or (B) irradiadons ranging from 4 to 340 Gy at the skin surface. All these techniques are not for isolated use and the present review indicates that their combination is necessary to give an improved diagnostic and prognostic picture of early and late delayed radiation damage to the skin and subcutaneous tissues.