鼻咽癌三维调强治疗中腮腺受照射剂量分析

Analysis on radiation doses of the parotid during intensity-modulated radiation therapy for nasopharyngeal carcinoma

目的探讨鼻咽癌(NPC)三维调强放疗(IMRT)中腮腺的受照射剂量。方法 IMRT放疗的NPC患者49例,通过剂量体积直方图(DVH)计算鼻咽原发灶(GTV1)、阳性颈淋巴结区(GTV2)的照射剂量、两侧腮腺接受一定剂量照射的体积(V25)以及两侧腮腺一定体积所受的照射剂量。结果 GTV1照射剂量(70.81±1.79)Gy,GTV2(65.84±1.94)Gy。腮腺V25照射剂量:左侧(93.78±5.96)%,右侧(93.60±13.46)%。腮腺50%体积所受的照射剂量:左侧(36.72±3.29)Gy,右侧(37.53±3.21)Gy。临床口干症状:1级5例,2级31例,3级13例。结论 NPB IMRT中腮腺的受照射剂量比常规放疗低;唾液腺得到较常规放射治疗很好的保护,但仍然不能解决口干的放射性损伤问题。

Objective：To analyze the radiation doses of the parotid during intensity-modulated radiation therapy（IMRT） for nasopharyngeal carcinoma（NPC）.Methods：With dose-volume histograms（DVH） of 49 patients with NPC treated by IMRT,radiation doaes were calculated for primary lesion（GTV1） and positive cervical lymph nodes（GTV2）.The volumes of bilateral parotid glands receiving irradiation of certain dose（V25） and irradiated doses in certain volume of parotid glands were calculated as well.Results：Doses of GTV1 and GTV2 were（70.81±1.79） Gy and（65.84±1.94） Gy,respectively.V25 of left and right parotid were（93.78±5.96）% and（93.6±13.46）%,respectively.Doses delivered to 50% volume of left and right parotid were（36.72±3.29） Gy and（37.53±3.21） Gy,respectively.Clinical xerostomia occurred in 5 patients with grade Ⅰ,31 cases with grade Ⅱ and 13 cases with grade Ⅲ.Conclusion：Lower doses are delivered to the parotid during IMRT and salivary gland is protected better compared with conventional radiation therapy,but radiation damage of xerostomia can not be avoided.