Recovery kinetics of X-ray damage in mouse skin: the influence of dose per fraction.
The rate of recovery from radiation damage, as a function of dose per fraction, was investigated in mouse skin. Two different experimental designs were used, both incorporating the neutron top-up technique which enables the X-ray dose per fraction to be kept constant whilst changing the interfraction interval. Either equally spaced X-ray fractions (concertina design) or single or multiple pairs of X-ray doses (single and multiple split-dose designs) were given at varying intervals, followed by graded doses of neutrons. A wide range of X-ray doses per fraction were investigated (from 1 to 10.5 Gy) and the data were analysed using the Thames Incomplete Repair (IR) model modified for use with neutron top-up doses. Analyses of the data, obtained from five different experiments, indicate that the rate of recovery from radiation damage is significantly faster at doses per fraction between 1 and 4.4 Gy than at 10.5 Gy. These data appear not to support the assumption, made by most recovery models, that the rate of recovery is independent of dose.
Rojas
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A
Cancer Research Campaign Gray Laboratory, Mount Vernon Hospital, Northwood, Middlesex, UK.
Joiner
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MC
Johns
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H
D000818:Animals; D004249:DNA Damage; D004260:DNA Repair; D004307:Dose-Response Relationship, Radiation; D005260:Female; D007700:Kinetics; D051379:Mice; D012867:Skin / Q000166:cytology / Q000528:radiation effects*