胸段食管癌5野和7野调强放疗计划的剂量学对比研究

Dosimetry comparison study between 5-field and 7-field IMRT planning for thoracic esophageal carcinoma

目的比较胸段食管癌5野调强放疗计划和7野调强放疗计划的靶区和相关危及器官的剂量学差异,为食管癌的放疗计划的设计提供参考。方法选择2015年7月至2017年2月在安徽医科大学第一附属医院接受调强放疗的30例胸段食管癌患者,患者分别设计5野和7野调强计划,比较2个治疗计划的靶区和危及器官的剂量学差异。结果 7野调强计划的靶区的适形指数和均匀指数均优于5野调强计划(P<0.05);5野调强计划的左右肺V_5低于7野调强计划,差异有统计学意义(P<0.05);但5野计划的左肺V_(20)、V_(30)及右肺的V_(20)高于7野计划,差异有统计学意义(P<0.05)。2种放疗计划的脊髓和心脏的剂量学参数差异无统计学意义(P>0.05)。结论 5野调强计划虽然没有7野调强计划的靶区适形度高,但是在减少肺部低剂量照射体积方面更具有优势,可以满足临床上大多数情况的要求。

Objective To compare the dosimetry differences between 5-field and 7-field IMRT plan for patients diagnosed with thoracic esophageal carcinoma,so as to provide reference for the plan design of clinical esophageal cancer treatment. Methods Thirty thoracic esophageal carcinoma patients received IMRT therapy in our institution were selected for study. We designed 5-field and 7-field IMRT plan for each esophageal cancer patients respectively. The dosimetric differences of target area and organs at risk（ OAR） were evaluated by dose volume histogram（ DVH）. Results Conformity Index（ CI） and Homogeneity Index（ HI） of 7-field IMRT plan was better than that of 5-field plan（ P 〈 0. 05）. However,the left lung V5 and right lung V5 were significantly lower than those of 7field plan（ P 〈 0. 05）. In addition,the left lung V20,V30 and right lung V20 of 7-field were obviously reduced compared with those of 5-field（ P 〈 0. 05）. There was no significant dosimetric difference in spinal cord and heart between these two plans. Conclusion Although the conformity of 5-field IMRT plan is no better than that of 7-field,the volume of lungs received lower irradiated dose significantly decreases when compared with 7-field. 5-field IMRT plan can meet clinical requirements in most situations.