Although rapid technological advanceshave led to a more precise delivery of radiation dose and to a decreased risk of side effects, there is still a significant need for personalized treatment to be achieved through the development of predictive tools that may guide therapy decisions. Indeed, the identificationof patients that are sensitive or resistant to RT could be used as a basis for tuning the appropriate therapeutic radiation dose for individual patients, optimizing thus the therapeutic gain in cancer treatment. Our aim is to develop and validate a reliable G2-chromosomal radiosensitivity assay (G2-assay) for personalized radiation therapy purposes and the prediction of individual radiosensitivity in clinical practice as well as to investigate the potential of combining radiation therapy with G2/M-checkpoint abrogators in vitro, e.g. caffeine or hyperthermia, to overcome radiation resistance of tumours and examine the molecular mechanisms involved. Finally, the efficiency of advanced radiotherapy techniques such as VMAT and IMRT delivered by Elekta linear accelerators is to be evaluated, using phantoms in conjunction with conventional as well as advanced cytogenetic techniques.