Quantitative analysis of the response of epidermis to two-dose irradiations

Abstract

Promising data have been obtained on the effects of non-standard fractionation schemes for the treatment of some types of tumours; the results show that some tissues and tumours are more radiosensitive when unconventional courses of fractionation are used (Sakamoto and Phillips 1979). This fact would indicate that some effects can be exerted by increasing or decreasing the time between fractions. The in vivo investigation of the intimate processes that occur in cells after split irradiations seems to be relevant. Epidermal cells react after irradiation, demonstrating a definite and measurable volume increase. This parameter, which has been characterized as dose-dependent and post-irradiation-time dependent (Lanfranchi et al. 1979, Klein Szanto et al. 1977) is related to the hyperactive State reached by epidermal cells during the acute phase of radiation injury (de Rey et al. 1979). Basal cell volume is a relatively easy end -point to measure and a reliable tool to express the in vivo effects using tissue sections. It also provides good evidence of the cellular behaviour after fractionated irradiations. In the present publication we have reported the results obtained measuring volume variations in basal cells in vivo after irradiation with single or two-dose irradiations, varying the time interval between the two fractions.