[Assessment of tolerance doses in multifractionated irradiation of the lung using Ellis and LQ models]

Ellis and LQ models were used to examine the tolerance dose dependences in different schemes of multifractionated radiation of the lung. For characterization of multifractionated radiation, a tolerance dose increment coefficient (TDIC) was introduced, which showed how the tolerance dose increased during multifractionated radiation as compared to the conventional scheme of dose fractionation with radiation given once a day. The Ellis models were shown to yield the TDIC values which were associated with the number of daily radiations rather than with the number of active days of radiation while the LQ models provides the TDIC values which depend not only on the number of daily radiations, but also on the number of active days of radiation. As the number of active radiation days increased, TDIC reduced. The studies were made according to a package of specially elaborated programmes which calculated tolerance doses in relation to the volume of radiation and to the scheme of dose fractionation in time, by using the TDF and LQ models.