[en] The importance of low-dos and low-dose-rate radiation induced has been well recognized. Different systems have been used to study this phenomenon induced by low doses and low dose rates of radiation using various biological endpoints such as chromosomal aberration and micronuclei. These results clear showed the occurrence of adaptive response in terms of hematopoietic microenvironment the conditioning given in small fractions continuously seemed to be more effective

[en] Human lymphocytes pre-exposed to low doses of ionizing radiation show an adaptive response, which make these cells less sensitive to subsequent higher exposures. To verify the hypothesis that a similar phenomenon can be induced by occupationally received doses of ionizing radiation, the cytogenetic responses of fourteen nuclear power plant workers to γ-irradiation was tested. Peripheral blood lymphocytes from nuclear power plant workers were tested for their sensitivity to induction of unstable chromosome aberrations by a subsequent exposure to a high dose of γ-irradiation (2Gy). The results show that lymphocytes of occupationally long-term exposed nuclear power plant workers are not sensitized and protected to subsequent high dose radiation with unstable chromosome aberrations induction