Engraftable stem cells expressed as fold decreases compared with nonirradiated controls.

The data presented in Figure 6 are presented here as a fold decrease in engraftment of post–1 Gy marrow at different times after 1 Gy compared with engraftment seen with nonirradiated marrow. Engraftments at 6 and 12 weeks are both significantly higher than at 0 weeks (Wilcoxon rank sum test, P < .001) and show an increasing time trend (Cuzick nonparametric trend test, P < .01). Data are expressed as a mean ± 1 SD.