Effect of cutoff of the population chain at different dose rates

. In the left diagram, factors between

-values for a specific

and log

-values

are shown. These values exhibit a nonlinear dose rate dependence but are nearly independent of the cumulative dose for a specific fractionation scheme (2 Gy fractions according to Figure

5). The situation becomes different for larger doses per fraction (example in the Figure

8 Gy fractions). Due to the high dose rate and the low

-value (1.45 h

^{−1}), the dose equivalent

does not reach a steady state and rises up to approximately 8 Gy (7.83 Gy). This leads to a higher repair rate and therefore to a slightly higher influence of the populations with

. In the right diagram, the differences of the

-values are given. This quantity is dependent of the cumulative dose (in this figure applied in fractions of 2 Gy) and can be approximated by an exponential function (for the discrete values of

).