The effects of varied numbers of dose fractions on the tolerance of normal human skin.
The early and late radiation of small areas of normal human skin, included in the treatment of basal cell carcinomata, have been used to evaluate the validity of the fractions exponent of the Ellis NSD equation. Fraction numbers at the lower end of the range used clinically were investigated (3 ,7 and 10 fractions); total doses were calculated using an NSD of 1930 ret with a fractions exponent of 0.22. Time and hence the time exponent was constant (14 days). The patterns of increasing and declining early skin reaction, measured using an arbitrary numerical scoring system, and the proportion of treatment fields reaching skin tolerance were similar for the three treatment groups. The number of treated areas showing late normal tissue damage were also similar. These observations suggest that it is legitimate to apply the NSD hypothesis to treatments involving 3-10 fractions over an interval of 14 days. Of particular interest was the observation that the final cosmetic result and tumour cure was not significantly improved by treatment given as 10 fractions over that obtained with 3 fractions.
D000328:Adult; D000368:Aged; D002280:Basal Cell Carcinoma / Q000532:radiotherapy*; D004307:Dose-Response Relationship, Radiation; D004890:Erythema / Q000209:etiology; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D010858:Pigmentation; D011830:Radiation Effects; D011879:Radiotherapy Dosage; D012867:Skin / Q000528:radiation effects*; D012878:Skin Neoplasms / Q000532:radiotherapy*