Cellular radiosensitivity of a rat brain tumor.
The response of a model brain tumor system in the rat to single doses of x irradiation has been studied.  Solid tumors were exposed in situ, removed, dissociated into single cells, and grown in tissue culture.  The fraciton of surviving clonogenic cells wasdetermined as a function of x-ray dose level for tumors irradiated in anesthetized, air-breathing rats, and for tumors irradiated in rats killed 5 minutes prior to irradiation bynitrogen gas asphyxiation.  The parameters of the survival curve for tumors irradiatedin air-breathing rats were: DO= 295 rads; DQ= 350 rads; and n= 3.0.  Similarly, thesurvival parameters for tumors irradiated in nitrogen gas asphyxiated rats were: DO=625 rads; DQ=675 rads; and n= 3.0. The survival curve of these tumor cells when assayed in in vitro tissue culture only has parameters of: DO= 225 rads; DQ= 350 rads; andn= 4.7.  Data form the in vivo to in vivo tumor cell survival curves suggest that there is no significant hypoxic fraction in this brain tumor.
D000818:Animals; D001254:Astrocytoma / Q000532:radiotherapy*; D001932:Brain Neoplasms / Q000532:radiotherapy*; D002470:Cell Survival; D002999:Clone Cells / Q000528:radiation effects; D046508:Culture Techniques; D008297:Male; D009374:Neoplasms, Experimental / Q000532:radiotherapy; D010100:Oxygen; D011830:Radiation Effects; D011879:Radiotherapy Dosage; D051381:Rats; D014964:X-Ray Therapy
D010100:Oxygen