【摘要】  　　［目的］探讨鼻咽癌（NPC）放射 治疗 后放射性脑病（REP）与放射治疗照射野设计的关系，寻求降低REP发生率的 方法 。 ［方法］ 回顾 分析 1992~2003年收治的NPC放疗后REP患者28例，采用Varian cadplan 三维治疗计划系统重新核算脑部病变部位剂量。 ［结果］ 全组病例最先出现脑部病变的部位均位于剂量热区，其剂量经核算均超过70Gy。 ［结论］ 颞侧对穿野的高剂量照射导致的颞叶剂量过高是REP发生的主因，可通过合理配比颞侧照射野与辅野如鼻前品字野的剂量比以减少REP的发生率。

【关键词】  鼻咽肿瘤　放射疗法　放射性脑病　照射野

　　Radiation Encephalopathy and Radiotherapeutic Field in

       Abstract: ［Purpose］ To investigate the relationship between radiation encephalopathy (REP) after radiation for nasopharyngeal carcinoma (NPC) and radiotherapeutic field design. ［Methods］ Twenty-eight cases with REP after radiotherapy for NPC from 1992 to 2003 were analyzed retrospectively. The delivery dose of brain injury was recalculated with Varian cadplan treatment planning system. ［Results］ The initial appearance of brain injury were located in dose hot spots in all the cases, with a dosage exceeding 70Gy. ［Conclusions］ Overdose of temporal lobe induced by high dose irradiation of temporal bilateral fields is the main cause of REP. Rate of REP can be reduced by adjusting the dose ratio of temporal bilateral fields to subfields such as frontnose field.

    Key words: nasopharyngeal neoplasms; radiotherapy; radiation encephalopathy; radiation field……