Estimation of relative biological effectiveness of tritium according to chromosome aberration frequency in human blood lymphocytes

The goal of this work was to determine the relative biological effectiveness (RBE) of tritium β-radiation according to the chromosome aberration frequency in the peripheral blood lymphocytes after in vitro and in vivo radiation exposures. The experimental RBE assessment of tritium β-radiation relative to ⁶⁰Co γ-radiation according to unstable chromosome aberration frequency in the peripheral blood lymphocytes under particular conditions is described. It has been demonstrated that tritium β-radiation is, in general, more effective in the dose range of up to 1 Gy, which is most pronounced at low doses. The RBE value of tritium β-radiation at minimum doses reached 2.2 and decreased at higher doses (1 Gy) to 1.25. The data on comparative analysis of the frequency of stable chromosome aberrations in the blood lymphocytes of professional nuclear workers (Sarov, Russia) after long-term chronic exposure to tritium β-radiation, as compared with γ-irradiation, are reported for the first time. The higher biological effectiveness of tritium β-radiation was demonstrated and was estimated as 2.5.