Cytological and Cytogenetic Damages of Spermatogonial Cells in Mice in the Acute and Late Periods after Irradiation by Protons, Helium Ions, and gamma-Rays

摘要

Experiments with small test animals have been carried out to study the survival rate of spermatogenic cells in the acute period after exposure to protons with the energy 9 GeV, helium ions with the energy 4 GeV/nucleon, and Co-60 gamma radiation in doses of 0.5-7.5 Gy and the reciprocal translocation frequency in spermatocytes under meiosis at the diakinesis-metaphase-1 stage six months after the exposure of the animals to protons with the energy 50 MeV and 9 GeV, helium ions with the energy 4 GeV/nucleon, and Co-60 gamma-radiation in doses of 0.5-4.0 Gy. It is shown that the dependence of the effect on the dose is linear or near to linear for all kinds of radiation used. Relative biological effectiveness coefficients of the accelerated nuclei obtained by correlating equally effective doses of the standard and investigated radiations turned out to be higher in survival rate of type B spermatogonium and amounted to 2.0 and 1.3 for 9 GeV protons and helium ions respectively. At the same time, the use of the nonparametric method to determine the R BE coefficients in the course of finding out the reciprocal translocation frequency in spermatocytes points to an increase in the RBE coefficients of charged particles from 1.0 to 2.0.