Biochemical indicators of radiation injury

Various techniques that utilize biomedical parameters are being employed to determine the degree of radiation damage and to relate it to the absorbed dose. The majority of these are based on biological responses to ionizing radiation, the degree of response being considered as proportional to the radiation dose, i. e. as dose dependent. Accordingly, these biological radiation responses have been termed 'biological dosimeters' or, more appropriately, 'biological indicators' of radiation damage. The ideal biological indicator of radiation damage would be one that is specific, sufficiently sensitive, suitable for detection of small radiation doses and would permit the determination of the degree of damage within the shortest possible time after irradiation. The ideal method should be simple and applicable to screening large numbers of people, if necessary. Of the biological indicators of radiation damage, the haematological lesions are the most generally used. Radio-haematological methods are employed to evaluate both changes in the peripheral blood and quantitative and qualitative changes in the bone marrow cells. These methods are also extensively used for devising the clinical treatment of persons suffering radiation damage. Unfortunately, radiation doses below 50 R do not induce changes in the peripheral blood that can be evaluated by these methods. It is an established fact that ionizing radiation alters the metabolism of cells, tissues and the whole organism. It is, therefore, understandable that attention has been focussed recently on the metabolic products produced in and excreted from the organism after irradiation. The results of metabolic studies in irradiated organisms and the possibilities for their use in practice are discussed