title: The comparative survival of clonogenic cells of a murine epithelioma irradiated in vivo with 250 kVp X rays, 60Co gamma rays, or negative pions produced by the cyclotron at TRIUMF.
abstract: Squamous carcinomas in WHT/Ht mice were exposed to the biomedical pion beam at TRIUMF. The biological effects of the pion beam were compared to those of 250 kVp x rays. The dose rates were 2-3 rad/min. (.02-.03 Gy/min.) for pions and 56 rad/min. (.56 Gy) for x rays. The surviving fraction of epithelioma cells irradiated in vivo was studied using the TD50 assay. RBE values for pions were calculated from the ratio of the x-ray and pion D0 values and were found to be 1.6 +/- 0.3 for oxic cells and 2.1 +/- 0.4 for hypoxic cells. OER values were 1.8 +/- 0.5 for pions and 2.4 +/- 0.4 for 250 kVp x rays.
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy*; D002470:Cell Survival; D002478:Cells, Cultured; D003037:Cobalt Radioisotopes; D004601:Elementary Particles; D005260:Female; D008297:Male; D051379:Mice; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000532:radiotherapy*; D010315:Particle Accelerators; D011882:Radiotherapy, High-Energy; D014965:X-Rays
chemical_list: D003037:Cobalt Radioisotopes