The use of hypoxic cell radiosensitizers with mixed X and alpha radiations.

When used alone, radiations of mixed LET will not completely eliminate the radioresistance of hypoxic cells. Hypoxic cell sensitizers also may not completely eliminate the problem because of toxic effects of the compounds at higher concentrations. Experiments were performed using a mixed LET 85 percent dose of x rays and a 15 percent dose of ..cap alpha.. particles from plutonium) and a 0.4 mM concentration of the hypoxic cell sensitizer Roche-07-0582. Cultures of both human cells (line T-1) and Chinese hamster (line CHO) cells were used in this investigation. The results indicate that the radioresistance of hypoxic cells can be dealt with more effectively by a combination of high-LET radiation and a hypoxic cell sensitizer than by either of these alone.