[en] It was shown by method of cytokinetic blocking that with neutron irradiation of human lymphocyte culture (mean energy of 0.85 MeV, doses of 0.05 to Gy) the dose-response relationship, with respect to the share of binuclear-cells with micronuclei in binuclear cells, was of a multiphase nature with a more or less manifest plateau within the dose-range from 0.5 to 1.0 Gy. Both micronuclear tests may be used for indicating the degree of radiation injury to the organism caused by neutrons of the above-mentioned energy and doses of 0.05-0.5 Gy