[The determination of the RBE of neutrons based on the hydroxyproline concentration in the lung tissue of irradiated piglets].

To test the radiogenic reaction of normal lung tissue experiments were done in 99 young pigs altogether. The radiation field included the total right lobe of the lung, 5 fractions of photons or neutrons (mean energy 6.2 MeV) were applied in a total treatment of 5 or 35 days. After killing the animals and taking the lungs the examination of tissue samples and others has been done for contents of hydroxyproline (HP) that has been used to register radiogenic injuries where the relation of irradiated and non-irradiated half of the same animal was estimated as measuring value. Above a limit of 1.13 for the HP-quotient (estimated in non-irradiated controls) there was a significant correlation with dose. Between the results of HP-quotients and histopathological findings a very good correlation was found. Calculation of RBE was done from relation of the dose values of photons and neutrons on base of the same level of injuries. In the tested total dose limit (photons: 14.25-38 Gy, neutrons 3.0-8.5 Gy) RBE-values of 3.8-4.5 were reached that correlates well with other tested criteria of the study in young pigs.