Empirical Evaluation of Cell Critical Volume Dose Vs. Cell Response Function for Pink Mutations in Tradescantia

摘要

Microdosimetric spectra for 0.43, 1.8, and 14.7 MeV neutrons, and for 215 kVp x rays and 1250 keV gammas were used in conjunction with relative biological effectiveness (RBE) values for pink mutations in Tradescantia to obtain an effectiveness function (i.e., a cell critical volume dose vs. cell response function). This effectiveness function (or hit size weighting function) provides the probability of inducing a biological effect of interest (in the present study, pink mutations in Tradescantia) as a function of lineal energy density y. In a preliminary analysis the critical value of y above which pink mutations are seen was 4.5 keV/ mu m, and the value of y at which the probability reaches unity was 115 keV/ mu m. Idealized but approximate event size distributions for mono-LET particles ranging from 10 to 5000 keV/ mu m were generated, and these distributions were weighted by the effectiveness function to determine the pink mutation frequencies. Results are compared with measured pink mutation frequencies for 11 keV/ mu m ( exp 12 C) and 31 keV/ mu m ( exp 20 Ne) ions. (ERA citation 07:062114)