Neoplasia in fast neutron-irradiated beagles.
One hundred fifty-one beagle dogs were irradiated with either photons or fast neutrons (15 MeV) to one of three dose-limiting normal tissues--spinal cord, lung, or brain. The radiation was given in four fractions per week for 5 weeks (spinal cord), 6 weeks (lung), or 7 weeks (brain) to total doses encompassing those given clinically for cancer management. To date, no nonirradiated dogs or photon-irradiated dogs have developed any neoplasms. Seven dogs receiving fast neutrons have developed 9 neoplasms within the irradiated field. Of the neutron-irradiated dogs at risk, the incidence of neoplasia was 15%. The latent period for radiation-induced cancers has varied from 1 to 4 1/2 years at this time in the study.
D000818:Animals; D004285:Dogs; D004307:Dose-Response Relationship, Radiation; D005214:Fast Neutrons; D009374:Neoplasms, Experimental / Q000209:etiology*; D009381:Neoplasms, Radiation-Induced / Q000209:etiology*; D009502:Neutrons