Quantitative assessment of dosimetric parameters of the radiation treatment plan for unplanned changes in the fractionation scheme

Abstract

Changes in the fractionation scheme of the radiotherapy course have an impact on the results of treatment of cancer patients. If changes in the fractionation scheme are not taken into account, this leads to under-irradiation of tumor cells and a possible occurrence of subsequent relapses. There are radiobiological models in order to take into account the errors in the radiation dose delivered to the tumor. They allow predicting the tumor control, as well as the toxicity level in normal tissues after traditional RT. The objective of the work is to assess the effectiveness of the absorbed dose in the event, if the fractionation scheme in the RT course changes, and to develop an algorithm that takes into account breaks between treatment sessions. In the study, the effectiveness of the radiation dose delivered to the tumor due to a change in the total treatment time is assessed analytically, a graphical dependence of the radiation dose efficiency on the duration of the unplanned interruption in the treatment of patients is built for the most common oncological localizations, an algorithm for radiotherapy procedures taking into account deviations from the standard radiation treatment pattern is developed.