Radiology, Vol 147, 839-844, Copyright © 1983 by Radiological Society of North America
Regional pulmonary function after irradiation of the canine lung: radionuclide evaluation
F Vieras, EW Bradley, PO Alderson, JP Jacobus and MP Grissom
The pulmonary effects of neutron and gamma irradiation were compared in a
group of beagle dogs that were subjected to hemithorax irradiation with
cobalt-60 gamma rays or 15-MeV neutrons. Integral cobalt-60 doses of 3000,
4500, or 6750 rad (30, 45, or 67.5 Gy) and neutron doses of 1000, 1500, or
2250 rad (10, 15, or 22.5 Gy) were given on a therapy- type schedule of
four equal fractions per week for 6 weeks. Serial Tc- 99m-macroaggregated
albumin perfusion, Tc-99m-Sn-phytate aerosol, and xenon-133 ventilation
studies were performed before irradiation and at 3, 6, 9, 12, 18, and 24
months postexposure. Pulmonary damage was more severe and persistent with
neutron than with gamma radiation, but the changes were dose-dependent for
both types of radiation. The perfusion and radioaerosol imaging studies
provided the best scintigraphic evidence of lung damage. Abnormalities in
the xenon-133 studies were relatively minor and were more apparent on the
single-breath than on the equilibrium or clearance studies. The
scintigraphic studies provided evidence of radiation-induced ventilation
perfusion inequalities with both types of radiation, but required several
times less neutron radiation than gamma radiation to produce similar
alterations in ventilation-perfusion relationships.
