title: Fractionated lung irradiation in young pigs with 6.2 MeV neutrons and cobalt-60.
abstract: Irradiations of the right lung with 6.2 MeV neutrons (38 test animals) and 60Co photons (34 test animals) were made using young pigs. Twenty animals were used as controls. Five fractions were administered in an overall treatment time of 5 or 35 days. The radiogenic pneumopathy was monitored with clinical, radiological and histological investigations, and by determining the hydroxyproline content in the lung tissue. The pneumopathy in pigs given neutrons developed after a shorter latency period and followed a more rapid and serious course than that in animals given gamma rays. While after photons the extension of the overall treatment time from 5 to 35 days led to a measurable but low increase of the ED50 this was not true for neutrons. The relative biological effectiveness (RBE) for the 6.2 MeV neutrons compared with 60Co photons was 4.0 for an overall treatment time of 5 days and 4.1 for 35 days.
mesh_terms: D000818:Animals; D003037:Cobalt Radioisotopes; D004307:Dose-Response Relationship, Radiation; D008168:Lung / Q000528:radiation effects*; D009502:Neutrons; D011882:Radiotherapy, High-Energy; D012062:Relative Biological Effectiveness; D013552:Swine
chemical_list: D003037:Cobalt Radioisotopes