Radionuclide Evaluation of Pulmonary Function Following Hemithorax Irradiation of Normal Dogs with60Co or Fast Neutrons

Abstract

To assess the effects of therapeutic doses of radiation on regional pulmonary function, 28 dogs had serial chest radiographs and quantitative ventilation, perfusion and aerosol studies at 3, 6, 9 and 12 mo. intervals after hemithorax irradiation with 60Co-gamma photons or 15 MeV fast neutrons. Findings showed marked reductions in perfusion and aerosol deposition in the irradiated lungs of dogs in the high-dose photon and neutron groups and in the medium-dose neutron group. The effects of large photon and small neutron doses were similar (neutron RBE [relative biological effectiveness] = 4.5). Radionuclide studies were useful for detecting these alterations.