Radiobiological Considerations in the Use of Total-Body Irradiation for Bone-Marrow Transplantation

Abstract

On radiobiological grounds, a therapeutic [human leukemia] advantage should result when total body irradiation (TBl) in preparation for bone-marrow engraftment is given as a fractionated course rather than as a single exposure at logistically reasonable dose rates. This is because cells of hemopoietic origin in general show less capacity for repair of sublethal radiation injury than do cells of other organs Dose-limiting lung tolerance, in the context of fractionated TBl, is estimated to be at least 12 Gy [gray] (without correction) in increments of 2 Gy regardless of dose rate. A practical method for delivering TBl using a high energy linear accelerator is described.