Résumé
Objective:To study the pathological changes of nasopharyngeal carcinoma cases after the treat-ment of stereotactic radiosurgery. Method: 15 cases with recurrent or residual squamous cell carcinoma of na-sopharynx diagnosed as T1～4 N0M0 were selected,which had undergone previous radiotherapy. The patients weretreated by Gamma Knife while the isodose curve was 50％00 and the margin dose was 20 Gy. The nasopharynxbiopsy was performed before the treatment and 1,3,6,12 months after the treatment. The biopsy specimen wastaken to make a pathological examination. Result:①Before the Gamma Knife treatment, carcinoma cell could beseen in the tissue;②1～3 months after the treatment, cell necrosis and acute inflammation cell infiltration couldbe seen in the target ;③6～12 months after the treatment ,infiltration of chronic inflammation cell ,proliferation offibrous tissue and capillary could be found in the target. Conclusion:This research implies that the short-termpathological changes after the treatment of stereotactic radiosurgery can be defined as two phases ..The first phaseoccurs from 1 to 3 months after the treatment called necrosis period. The second phase occurs from 6 to 12months after the Gamma Knife treatment named as absorption period.