固定准直器技术在食管癌根治性放射治疗中的应用

Application of Fixed Collimator in Radical Radiotherapy for Esophageal Cancer

目的在食管癌根治性放射治疗中应用固定准直器(FC)技术进行调强放射治疗(IMRT)计划设计,以期在达到计划靶区(PTV)目标剂量分布的同时降低危及器官(OAR)的受照射剂量,特别是降低肺部低剂量区的受照射体积。方法应用瓦里安Ecplise 13.5放射治疗计划系统(TPS),选取2018年1月1日至2020年1月1日于徐州市肿瘤医院进行食管癌根治性放射治疗的20例患者,采用同一物理参数,应用FC技术与自动准直器(AC)技术设计IMRT计划,比较FC计划与AC计划的PTV剂量学参数、OAR剂量学参数、执行效率及3%/3 mm标准下的γ通过率。结果两组计划的PTV计量学参数比较,差异均无统计学意义(P>0.05),均能满足临床需求。FC计划的双肺V_(5)和D_(mean)均低于AC计划,差异有统计学意义(P<0.05);两组计划的其他OAR剂量学参数比较,差异均无统计学意义(P>0.05)。两组计划的总机器跳数(MU)、治疗时间比较,差异均无统计学意义(P>0.05)。两组的γ通过率比较,差异无统计学意义(P>0.05),但均达到了95%以上,满足临床需求。结论应用FC技术进行IMRT,可有效保护肺部低剂量区,可将其作为食管癌根治性放射治疗的重要补充。

Objective The fixed collimator(FC)technique was applied to design the intensity modulated radiation therapy(IMRT)plan in radical radiotherapy for esophageal cancer to meet the dose distribution requirements of planning target volume(PTV)and meanwhile reduce the radiation dose of organ at risk(OAR),especially reduce the radiation volume of low-dose area of lungs.Methods A total of 20 patients who received radical radiotherapy for esophageal cancer in Xuzhou Cancer Hospital from January 1,2018 to January 1,2020 were selected.The Eclipse 13.5 treatment planning system(TPS)was applied to design IMRT plans by FC and auto collimator(AC),respectively,using the same group of physical parameters.The dosimetry parameters of PTV and OAR,the implementation efficiency,and theγpass rate with the standard of 3%/3 mm were compared between FC and AC plans.Results When the dosimetry parameters of PTV of the two plans were compared,the differences were not statistically significant(P>0.05),and both of them could meet the clinical requirements.The V_(5) and D_(mean) of bilateral lung of the FC plan were lower than those of the AC plan,and the differences were statistically significant(P<0.05);When the dosimetry parameters of the other OARs of the two plans were compared,the differences were not statistically significant(P>0.05).When the total MU and treatment time of the two plans were compared,the differences were not statistically significant(P>0.05).When theγpass rate of the two plans was compared,the difference was not statistically significant(P>0.05),but both reached more than 95%and could meet the clinical requirements.Conclusion The application of FC in the IMRT could effectively protect the low dose area of lungs,so it could be served as an important supplement for radical radiotherapy of esophageal cancer.