Applying radiation induced tissue damage models to cell-colony data analysis and dose-volume constraint estimation

The effects of radiation damage, tumour repopulation, repair and the possibility to extract information about the model parameters describing them are investigated. Published data on cultured cell lines were analyzed by employing a non-Poissonian tumour control probability model. A report in the literature, where in-vivo data were analyzed, the employment of the single-hit model of cell kill and cell repopulation produced the best fit. Ignoring the quadratic term of cell damage in the current analysis leads to poor fits. Our data analysis shows the importance of the linear-quadratic mechanism of cell damage for the description of the in-vitro cell dynamics.; The possibility of calculating more radiobiologically adequate dose-volume constraints for the needs of the radiation treatment optimization is investigated. Based on the Lyman and the critical volume normal tissue complication probability (NTCP) models, the Monte-Carlo method of reverse NTCP mapping is applied for the calculation of new dose-volume constraint information.