(A) Axial, saggital and coronal CT images showing the final intensity-modulated radiation therapy (IMRT) plan and isodose distributions around the tumor bed. Gross tumor volume (GTV) is outlined from contrast enhanced planning CT scan. Isodose lines of decreasing energies radiate out from the center of the tumor bed. The tumor is completely contained by the 95% isodose blue line (57 Gy). (B) Cumulative dose-volume histogram (DVH) of the IMRT plan. The curves illustrate the dose distribution for the clinical target volume (CTV: defined as GTV +0.5 cm), mandible, left parotid, optic nerves, optic chiasm and a cervical lymph node.