Figure 1: Diagrammatic representation of the experimental design to evaluate the effect of low-dose, whole body 90 cGy, 1 GeV 1H and 15 cGy, 1 GeV/n 56Fe-IR in BM-derived EPCs of 8–10 months old C57BL/6NTac. (a) In vitro study schematic for IR-conditioned medium transfer study to evaluate bystander responses in nonirradiated BM-EPCs over 24-hour time period after IR. (b) Ex vivo study schematic to evaluate the effects of full-body IR over 28 days on survival of BM-EPCs.