非共面照射技术对鼻咽癌筛窦侵犯的剂量分析

Dose Analysis of Non Coplanar Irradiation Technique for Ethmoid Sinus Involvement of Nasopharyngeal Carcinoma

目的探讨鼻咽癌筛窦侵犯调强放疗中非共面射野对正常组织的保护和提高肿瘤区的剂量。方法收集鼻咽癌筛窦侵犯患者15例,每一例患者设计2种射野方案,Ⅰ方案采用9野共面照射技术,Ⅱ方案采用9野和1野非共面照射技术。结果 2种方案比较发现:加设非共面射野能够有效改善正常组织的剂量,腮腺30Gy的照射体积减少10%以上。靶区剂量明显提高,适形性指数CI平均提高8%,均匀性指数HI平均提高6%。结论非共面照射技术在鼻咽癌筛窦调强放疗中对正常组织有保护作用并可提高肿瘤区剂量。

Objective To investigate the dose of non coplanar radiation technology for ethmoid sinus involvement of nasopharyngeal carcinoma.Methods Collect 15 cases of patients with metastatic nasopharyngeal carcinoma of ethmoid sinus; each patient was treated with 2 sets of field programs,1 treatment used 9 fields coplanar irradiation technology,another use 9 fields and1 field non coplanar irradiation technology.Results In comparison of the 2 groups of field case： adding non coplanar field can effectively improve the dose of normal tissue; the irradiation volume of 30 Gy in parotid gland could be reduced by more than 10%.Target dose increased significantly,conformal index increased by 8%,homogeneity index increased by 6%.Conclusion Non coplanar radiation technology for ethmoid sinus involvement of nasopharyngeal carcinoma can protect normal tissues and improve tumor dose.