摘要
目的 探讨大体靶区（GTV）分区勾画对椎前间隙受侵局部晚期鼻咽癌调强放疗疗效的影响.方法 收集伴有椎前间隙受侵局部晚期鼻咽癌（Ⅲ-Ⅳa）20例,采用两种方法勾画靶区：第一种方法（Plan1）对于近脑干、脊髓GTV分区勾画,最接近脑干、脊髓肿瘤勾画一亚靶区（GTVsv）,并且对于GTV、GTVsv分区给量;第二种方法（Plan2）按传统方法勾画靶区.利用pinnacle调强治疗计划系统设计调强计划分两段执行.比较Plan1和Plan2靶区和正常组织的剂量分布以及靶区适形度和均匀指数.结果 Plan1和Plan2中大体肿瘤的计划靶区（PGTV） ＜93％处方剂量的体积分别为[（0.63±0.21）％,（0.68±0.10）％,P=0.049];PGTV＞ 110％处方剂量的体积分别为[（11.59±7.01）％,（12.71±6.03）％,P=0.041];PGTV＞ 115％处方剂量的体积分别为[（2.05±0.80）％,（2.76±1.14）％],差异有统计学意义（P =0.049）.Plan1和Plan2中脊髓最大剂量分别为（41.00±4.52） Gy vs（45.00± 3.25）Gy,两计划比较差异有统计学意义（P=0.048）.Plan1靶区剂量均匀性及适形度好于Plan2,但差异无统计学意义（P＞0.05）.结论 GTV分区勾画、分区给量,分程调强优化了椎前间隙受侵局部晚期鼻咽癌的调强计划,改善了靶区适形度及均匀性,减少了靶区低剂量区,降低脑干、脊髓受量.此种方法在理论上和剂量学上具有可行性,对于此种方法的临床推广应用还有待于大样本的观察验证.
Objective To explore the dosimetric effect of using a split of the gross tumor volume （GTV） delineation approach during intensity-modulated radiotherapy （IMRT） treatment planning for advanced T-stage nasopharyngeal carcinoma （NPC） with prevertebral space involvement （PSI）.Methods Twenty NPC patients with T3-T4 tumors with prevertebral space involvement were studied.Two kinds of plans were generated based on the same protocol.The first plan was GTV-split consisting of organ at risk （including spine cord and brain stem） overlapping and non-overlapping subsegments.The subsegments were assigned independent dose constraint.The second plan was done based on a standard treatment planning protocol.The two plans were compared with respect to target coverage and organ at risk （OAR） sparing,and target conformity index.Results Two plans both met requirement of dose coverage of target and constraints on normal tissue.Regarding the planning gross target volume （PGTV）,the doses of 〈 93% volume of plan 1 and plan 2 were [（0.63 ± 0.21）%,and （0.68 ± 0.10）%,P =0.049];the doses of 〉 110% volume of plan 1 and plan 2 were [（11.59 ± 7.Ol） %,and （12.71 ± 6.03） %,P =0.041];the doses of 〉115% volume of plan 1 and plan 2 were [（2.05 ± 0.80）%,and （2.76 ± 1.14）%,P =0.049];about OARs,the maximal dose of spine cord for plan 1 and plan 2 were （41.00 ± 4.52） Gy and （45.00 ± 3.25） Gy （P =0.048）;and the target coverage and target conformity index of plan 1 were better than those of plan 2,the p-values were 0.063,and 0.135,respectively.The difference between two plans was statistically significant （P 〈 0.05）.Conclusions A split-GTV delineation,independent dose constraint,and multi-course IMRT for advanced T-stage nasopharyngeal carcinoma with prevertebral space involvement optimized IMRT treatment planning,improved target coverage and target conformity index,and decreased the maximal dose for the spine cord and brain stem.It is feasible and has advantage to decrease
出处
《中国医师杂志》
CAS
2016年第3期394-397,共4页
Journal of Chinese Physician
