Radiation biological investigations with multi cellular spheroids as an in vitro tumor model part 3 comparative investigations of single cell survival after irradiation of v 79 4 multi cellular spheroids with x rays or fast neutrons
Studia Biophysica 70(2): 161-162
In view of interest in the application of fast neutrons to cancer therapy comparative studies were done on the survival of V79-4 Chinese hamster [lung] multicellular spheroid single cells after irradiation with X-rays or fast neutrons, because the spheroid system seems to be a useful in vitro tumor model. After irradiation of spheroids with fast neutrons (300-400 .mu.m and 600 .mu.m) also multicomponent survival curves were found, although the fraction of the high radioresistant hypoxic spheroid cells was increased (due to the irradiation conditions) and these cells were killed more efficiently. The slopes of the exponential parts of the survival curves of spheroid cells and anoxic monolayer single cells are identical, indicating that the special conditions leading to increased survival fraction of hypoxic spheroid cells after X-irradiation, after fast neutron irradiation seem to be eliminated. A split-dose effect after irradiation of spheroids with fast neutrons could not be found; the survival fraction seems to be decreased.