A mathematical model of fractionated telegammatherapy of a tumor consisting of well-oxygenated and hypoxic cells

A mathematical model of an irradiated tumor consisting of well-oxygenated and hypoxic cells is built, with the aim of finding optimum fractionation protocols. Optimum doses per fraction are, as a rule, higher then those used conventionally. Assuming that the value of NSD for any critical organ is similar to that during standard fractionation, optimum fractionation protocols provide a small gain expressed in terms of the survival rate of tumor cells in general. It was found that the number of fractions in the above model is not a good parameter in the ''nominal tumor dose'' formalism, and it should be replaced by the dose per fraction. 9 refs., 6 figs., 2 tabs. (author)