**4.2 Treatment**

The radiation therapy regimen consisted of ultrafractionated focal irradiation with three daily doses of 0.75 Gy delivered at least four hours apart five days a week (Monday through Friday), for 6-7 consecutive weeks. A total dose of 67.5 Gy was delivered in 90 fractions (Beauchesne et al., 2010). Irradiation was delivered to the gross tumor volume with a 2.5 cm margin for the clinical target volume. Radiation therapy was planned with dedicated computed tomography (CT) or magnetic resonance imaging (MRI), and three-dimensional planning systems; conformal ultrafractionated radiotherapy was delivered with linear accelerators with a nominal energy of 6 MeV or more (Beauchesne et al., 2010). The patients were treated with thermoplastic immobilization masks to ensure adequate immobilization and reproducibility.
