From the early 1900s, it has been known that ionizing radiation (IR) impairs hematopoiesis
through a variety of mechanisms. IR exposure directly damages hematopoietic stem cells
and alters the capacity of bone marrow stromal elements to support and/or maintain
hematopoiesis in vivo and in vitro. Exposure to IR induces dose-dependent declines in
circulating hematopoietic cells not only through reduced bone marrow production, but also
by redistribution and apoptosis of mature formed elements of the blood. Recently, the …