title: Response of human organs to single (or fractionated equivalent) doses of irradiation.
abstract: Characteristics of the kinetics of radiation response of human tissues and organs are exemplified by effects in the testis and the ovary. Also, published dose-incidence curves for specified levels of injury in bone marrow, liver, bladder and lung are characterised in terms of single doses as well as single-dose equivalents calculated from fractionated doses using the alpha/beta equation. It is shown that these curves, analysed using a Poisson model, have slopes characterised by D0-equivalents ranging between 1.25 and 2.5 Gy. These values are higher or within the range of values reported in general for single-dose survival curves of human cells in primary culture (range of D0 values 0.7-1.8 Gy). This indicates that single-cell responses together with other complicating biological and statistical sources of heterogeneity under discussion, could form a basis for explaining the steepness of dose-incidence curves for organ injury after fractionated doses. With local organ irradiation, increase in the single-dose equivalent by 3-10 per cent would increase the complication rate from 5 per cent to 10 per cent. Higher dosage increases (by up to two times) apply to fractionated doses.
authors.affiliation: Department of Radiobiology, Paterson Institute for Cancer Research, Christie Hospital, Manchester, U.K.
authors.forename: J H
authors.initials: JH
authors.lastname: Hendry
mesh_terms: D001853:Bone Marrow / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008099:Liver / Q000528:radiation effects; D008168:Lung / Q000528:radiation effects; D008297:Male; D010053:Ovary / Q000528:radiation effects; D014022:Tissue Survival / Q000528:radiation effects*; D001743:Urinary Bladder / Q000528:radiation effects