Abstract: Objective To investigate clinical features，MRI findings, radiation volume and dose, and prognosis of irradiated temporal lobe injury in local advanced nasopharyngeal carcinoma infilatrating cavernous sinus after intensity modulated radiation therapy（IMRT）. Methods From Aug 2006 to Sep 2011, ten patients with cavernous sinus invasion in locally advanced nasopharyngeal carcinoma receiving radical IMRT were retrospectively analyzed. The total volume，dose volume D1 ml Dmax and Dmean of irradiated ipsilateral temporal lobe in radiotherapy planning were examined. Clinical features，MRI findings and prognosis of these patients after treatment were investigated.
Results The irradiated ipsilateral temporal lobe total volume and dose volume of IMRT of the 10 ten patients were as follows. The total volume was（104.31±13.091）ml，D1 ml was（78.657±2.918）Gy，Dmax was（78.298±3.498）Gy and Dmean was（29.488±8.891）Gy. The radiation induced temporal lobe injury presented 2-4 years after radiation in the 10 followed-up patients. MRI findings showed T1WI with high signal reinforced nodular lesions or sheet strengthening and T2WI with varying degrees of edema. Till August 2016，2 patients died；2 patients were with heavy symptoms and the symptoms were not improved obviously after treatment，and meanwhile，MRI showed enhancement and edema；2 patients were significantly improved in clinical symptoms and MRI findings after symptomatic treatment；4 patients with stable disease and MRI of 2 patients showed small recovery cystic foci formation. Conclusion The incidence of irradiated temporal lobe injury in cavernous sinus of locally advanced nasopharyngeal carcinoma after IMRT were associated with the area of tumor invasion，the scope of target delineation and the irradiated volume and dose.