[An experimental model for adjusting the rhythm of irradiation to the kinetics of the tissues to be irradiated].
To obtain better results with radiotherapy it is necessary to take into account the tissue kinetics. Synchronized cell cultures in vitro show that the radiation-induced mitotic delay and the survival curves are cell phase-dependent. It is necessary to follow the evolution of the different cell populations in the irradiated volume. It can be done using a distribution factor (fD), that may be defined as the quotient between the number of S-phase cells and the number of cells in the remaining phases at a given moment.