A Comparison of Radium and Californium 252 Using Cultured Mammalian Cells

Chinese hamster cells were irradiated at various low-dose rates with radium gamma rays and with the mixed neutron and gamma emission from californium 252. Cell killing was unaffected by a dose-rate change from 1.14 to 21.4 rads/hour for californium. For radium there was a continuous reduction in cell-killing effect as the dose rate was reduced from 52.5 to 11.7 rads/hour. It is suggested that 890 rads of californium neutrons in a time period close to seven days is equivalent to the standard treatment of 6,000 rads of radium gamma rays in seven days.