Radionuclide evaluation of pulmonary function following hemithorax irradiation of normal dogs with 60Co or fast neutrons.

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 three-, six-, nine-, and twelve-month intervals after hemithorax irradiation with 60-Co-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 = 4.5). Radionuclide studies were found to be useful for detecting these alterations.