Dose response curves for clonogenic cell survival or functional impairment of irradiated normal tissues

We welcome the comments by Fowler (1983) on our recent paper (Wheldon et al, 1982), and in particular his agreement on the need to distinguish clearly between the dose-response curves for gross injury and/or impairment of tissue function and those for reproductive survival of clonogenic cells. Fowler points out that “There must be some relationship between them but it is not necessarily independent of radiation dose”. In our recent model of the radiation responses of slowly proliferating normal tissues (“Type F” tissues, Wheldon et al, 1982) this relationship is indeed shown to be dose-dependent and leads to a systematic difference in shape between the two dose-response curves.