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Treatment personalization in patients with hypoxic tumours: The role of radiobiological models.

Strigari L., Attili A.
  Venerdì 15/09   09:00 - 12:00   Aula A204   V - Biofisica e fisica medica
The personalization of radiotherapeutic treatment should necessarily be based on tumour and patient radiosensitivity through the use of appropriate radiobiological models. In the case of hypoxic tumours, several authors have proposed models for determining the oxygen enhancement ratio (OER) ratio, with the aim of including this parameter in the treatment planning systems for both photons and ion-therapy. In this communication the biological effective dose (BED) has been calculated based on radiobiological models obtained from $in vitro$ survival fraction of some reference cells (such as HSG, V79 and CHO) as a function of dose, partial oxygen concentration, and particle type. BED has been also calculated using radiobiological models and parameters based on clinical trials. Considering 3 representative patients with targets containing different fraction of hypoxic cells the impact on treatment planning of different models was investigated. The three-dimensional (3D) BED distributions were compared in terms of dose difference and 3D gamma index (2%, 2mm). Similarly, the difference in BED-volume histogram was estimated using the gamma index (2%, 2mm). The obtained results and the expected radiotherapeutic impact are discussed in order to optimize the therapeutic strategy.