Session

Overview: Conventional GTV/CTV definition is intrinsically affected by large uncertainties, often reflecting in potentially redundant treated volumes. Innovative approaches aimed to include uncertainties due to delineation and to the microscopic spread around GTV are under development and testing with the potential of incorporating them within modified plan optimization methodologies. Quantitative models of tumor progression and local/regional spread may “a priori” help in individually optimizing CTV definition. Then, probabilistic approaches of CTV definition alternative to the ICRU binary definition can be integrated into probabilistic planning approaches, promising to manage the traditional trade-off between target dose coverage and sparing of OARS in new (and safe) ways, likely to result in future better treatments