胸上段食管癌同步整合加量调强放射治疗逆向计划与正向计划的剂量学差异

Dosimetric difference of inverse and forward SIB-IMRT for upper thoracic esophageal carcinoma

目的探讨胸上段食管癌同步整合加量调强放射治疗逆向计划与正向计划的剂量学差异。方法对10例胸上段食管癌患者分别设计静态逆向调强同步集合推量与静态正向调强野中野肿瘤区同步加量两种放射治疗计划,比较两种计划的靶区剂量、危及器官的受照剂量体积差异等指标。结果两种计划均能满足临床剂量学要求。逆向计划的适形指数、剂量均匀指数、最大剂量、最小剂量、平均剂量、靶区接受剂量95%等剂量线所包括的体积百分比、脊髓最大剂量、平均肺剂量以及肺接受20、30Gy照射的肺体积占全肺总体积的百分比均优于正向计划(P<0.01或P<0.05)。而正向计划的肺接受5Gy照射的肺体积占全肺总体积的百分比及子野数目、总跳数、治疗时间、计划设计时间均优于逆向计划(P<0.01)。结论同步整合加量逆向调强放射治疗技术可能是胸上段食管癌患者行根治性放射治疗的更好选择。

Objective To investigate the dosimetric difference between inverse and forward simultaneous integrated boost（SIB）-intensity modulated radiation therapy（IMRT）for upper thoracic esophageal carcinoma.Methods Two radiotherapy plans in ten patients with upper thoracic esophageal carcinoma were performed by static IMRT with SIB（group A）and field in field technique（group B）,respectively.Dosimetric evaluation parameters and absorbed dose of organs at risk were compared between two groups.Results Both inverse and forward SIB-IMRT were acceptable in clinical dosimetry.The conformity index,heterogeneity index Dmax,Dmin,Dmean,V95%,Dmax of spinal cord,mean lung dose,V20 and V30in group A were better than those in group B（P〈0.01 or P〈0.05）.While V5,total number of segments,total number of monitor units,treatment time and plan-producing time in group B were better than those in group A（P〈0.01）.Conclusion Inverse SIB-IMRT seems to be a better choice for the patients with upper thoracic esophageal carcinoma.