[Use of multicellular spheroids in studies based on the NSD (nominal standard dose) concept].

The authors discuss the possibility of application of multicellular spheroids as a model system in studies based on NSD conception. The death rate of spheroids from cells of Chinese hamster V79-4 was shown to depend upon cumulative dose of gamma- and neutron (0.7 MeV)-radiation (the number of fractions was 1, 5 and 10). With fractionated irradiation, the reoxygenation effect was observed. A good coincidence was obtained between the dependence of the cumulative dose upon the number of fractions for multicellular spheroids and clinical data.