Figure 4.

Combined effect of labeled fraction and of activity distribution on the cell survival-response of labeled cells when a 1000-keV monoenergetic electron emitter is lognormally distributed among the labeled cells. From left to right, the percentage of cells labeled is 100%, 50%, 10%, and 1%. The surviving fraction of mixed cells is plotted as a function of mean absorbed dose to all cell nuclei. The activity distribution is uniform (σ → 0) or lognormal with shape parameters of σ = 0.6, 1.0, and 2.0. The dashed lower and upper lines represent exponential survival curves with D₃₇ = D_37,self = 1.2 Gy and D₃₇ = D_37,cross = 4.0 Gy, respectively. A complete set of curves for all combinations of energy and fraction of cells labeled is provided in Fig. 4 of the supplementary material (B) (Ref. ⁵⁰). For the sake of comparison, the data for 100% labeling are reproduced from Rajon et al. (Ref. ³²).