Fig. 1

Isodose distribution in a patient with nasopharyngeal carcinoma (NPC) extending to the right cavernous sinus. The right temporal lobe is close to the tumor. The gross tumor volume is delineated with a red line. Most of the tumor was underdosed. Although the maximum point dose of the right temporal lobe was 66.0 Gy, 95% of it received less than 60 Gy. The eyes, brain stem, left temporal lobe, optic chiasm, and optic nerves were spared from high-dose radiation