In order to use appropriately NAT and explore possibility of use of the test in human cells, the authors used gamma-rays as mutagenic and carcinogenic irradiated whole blood in vitro, prepared directly smears of isolated lymphocytes, and studied comparatively dose-response relationship of 4 types of nuclear damage. Main results of the study are given as follows: 1. In doses from 0 to 3 Grays MNF (Frequency of micronucleus), INF (Frequency of irregular nucleus), KNF (Frequency of karyorrhetic nucleus), and PNF (Frequency of pyknotic nucleus) increase along with increase of irradiated doses. At 5 grays INF still increases, but MNF, KNF and PNF decrease. 2. In doses from 0 to 3 grays regression equation of 4 indices of nuclear damage are as follows (D means dose, r means correlative coefficient): MNF: y = 0.3433 + 0.1052D, r = 0.9128, p less than 0.05; INF: y = 7.2178 + 2.1817D, r = 0.8846, p less than 0.05; KNF: y = 0.6462 + 0.2014D, r = 0.7286, p greater than 0.05; PNF: y = 0.2774 + 0.0728D, r = 0.5484, p greater than 0.05. 3. In doses from 0 to 3 grays MNF is linear with INF and KNF. Regression equation are as follows (x means MNF): MNF-INF: y = 2.0598 + 16.6545x, r = 0.778 p greater than 0.05; MNF-KNF: y = 0.2235 + 1.426x, r = 0.5945, p greater than 0.05. Finally according to synthetic analysis of correlative coefficient, intercept, regression coefficient and feasibility of indices of nuclear damage, we could consider it suitable that nuclear anomalies in human peripheral lymphocytes include micronucleus, irregular nucleus and karyorrhexis.