3D treatment planning in radiotherapy of gliomas. A dosimetric analyses of cerebral irradiation

The goal of this study is to analyze the possible advantage of the three dimensional (3D) conformal radiation treatment in comparison with a two dimensional (2D) conventional technique and to present the clinical results of the treatment in 60 patients with high grade gliomas. The patients received a total radiation dose of 60 Gy, 2 Gy/day. The survival rate was analyzed with the Kaplan Meier curve. In 10 patients a 3D treatment planning was compared with a conventional 2D planning: the volume of the normal brain tissue irradiated to high dose levels (95% isodose) and the normal tissue complication probability for the brain and for the optical chiasma - NTCP by Kutcher and Lyman, were comparatively analyzed. The 3D conformal radiation therapy spares 15-20% of the normal brain tissue in comparison to the 2D technique. The sparing of the normal brain tissue will be useful for dose escalation studies.