[Dose-time correlation in the irradiation of the lung of piglets for evaluating a model of human radiogenic pneumopathy].

Dose-time relationships with respect to a pulmonary radiogenic reaction were studied in 62 improved-breed pigs aged 3 mos. with the mass of 20-30 kg. The animals received fractionated irradiation with 60Co. Irradiation and its doses were computed in a way similar to that used in clinical practice. Clinical evidence, respiration rate, chest x-ray, histological and biochemical investigations of pulmonary tissue served as quantitative criteria of pulmonary lesion. ED50 was determined, i.e. a dose at which 50% of the experimental animals fell ill. The number of fractions produced a greater effect on an isoeffect curve than the entire period of irradiation. The pulmonary radiogenic reaction in pigs could be expressed by the calculation D approximately N0,32 T0,05. A possibility to introduce the results of the experiments on pigs into clinical practice allows practical use of the dose-time relationships obtained in the experimental studies.