Optimization of radiation therapy for tumors: problem of radiation dose fractionation

The problem of optimal fractionation of the radiation dose remains a key one from the standpoint of a possible increase in the effectiveness of radiation therapy. The basic model of clinical radiobiology on the dynamics of tumor growth under radiation exposure taking into account the proportion of dividing and hypoxic cancer cells is considered. Two scenarios for applying radiation loads are compared: uniform fractionation and dynamic fractionation. Under both scenarios, the values of the total radiation doses and the total duration of treatment (50 Gy, 5 weeks) do not change. After carrying out numerical experiments on a computer, it was found that in the regime of dynamic fractionation of the radiation dose, the number of surviving cancer cells is 11 times less than in the regime of uniform fractionation. The result obtained is of fundamental importance in minimizing the number of relapses at the stages of the tumor process T3, T4.