鼻咽癌调强放疗国内外委员会推荐剂量差异性分析

The difference analysis of prescription dose between ICRU report 83 and Chinese recommendation in the nasopharyngeal carcinoma when using

目的分析ICRU83号报告与中国鼻咽癌临床分期工作委员会推荐的鼻咽癌调强放疗处方剂量要求的差异性。方法回顾分析2010-2012年间治疗的84例鼻咽癌调强放疗计划的剂量体积直方图，分别记录原发灶计划大体肿瘤体积（PGTVmx）和计划高危临床靶体积-1（PCTV1）的体积和百分x体积接受的剂量（Dx），计算上述读取内容的平均值、标准差、中位数、最小值、最大值、变异系数，以及PTVnx和PCTV1的均匀性指数及D95，和D50之间偏差。分组结果比较采用成组t检验。结果PGTVnx，和PCTV1的均匀性指数分别为0．118±0．045和0．272±0．037，PGTVnx靶区体积越大，T分期越晚，HI越差。PGTVnx和PCTV1的D95均〈D50平均偏差分别为-5．15％和-10．97％；实际差值分别为（382±180）cGy（P=0．000）和（41±140）cGy（P=0．000）。结论D50作为ICRU83号报告推荐的计划靶体积处方剂量，结合D98和D2能更准确评估调强放疔计划。如果用D50替代D95作为处方剂量，则PGTVnx，和PCTV1需分别增加5％和11％剂量才能达到相似的预期肿瘤局部控制率。

Objective To analyze the difference of prescription dose between ICRU report 83 and Chinese recommendation in the nasopharyngeal carcinoma （NPC） for intensity modulated radiation therapy （IMRT）. Methods Eighty-four NPC were treated using IMRT technology from Jan 1, 2010 to Apr 1, 2012. All dose volume histogram of the 84 IMRT plan were analyzed retrospectively. The target volumes of planning gross tumor volume of nasopharynx （PGTVnx） or planning clinical target volume and high risk lymphatic drainage （ PCTVl ） and doses of D100, D98 , D95, D50, D2 and Do were recorded. The mean, standard error, medial, range, coefficient of variation （CV） of PGTVnx, PCTV1 , and D100, D98 , D95 , D50, D2 and DO were calculated, respectively. The homogeneity index （HI） and deviation between D95 and D50 of PGTV and PCTV1 were calculated, respectively. The differentiation of grouping results were analyzed with grouped t-test method. Results The HI of PGTVnx and PCTV1 were 0.118 ±0. 045 and 0. 272 ± 0. 037, respectively. It is the bigger target volume, the worse HI;and the advanced T stage, the worse HI. Either PGTVnx or PCTVI, D95 were less than D50. The average deviation was -5.15% and -10. 97% , and the actual difference value was （382±180） cGy （P= 0.000） and （741±140） cGy （P= 0.000）. Conclusions Dso, which is the recommendation prescription dose of PTV in ICRU report 83, could evaluate accurately the IMRT plan with combining D98 and D2. When D50 is used to instand of D95 , the prescription dose of PGTVnx and PCTV1 should increase 5% and 11% , respectively.