三种剂量验证系统在直肠癌容积旋转调强放疗计划中的验证结果比较

Comparison Verification Results of Three Dose Verification Systems in the Volumetric Modulated Arc Therapy Plan for Rectal Cancer

目的 比较和分析Delta4、EDose和Portal Dosimetry(PD)3种剂量验证系统在直肠癌容积旋转调强放疗(VMAT)计划中的剂量验证结果,为剂量验证选择合适的验证方法和评价标准。方法 回顾性选取在福建医科大学附属协和医院行VMAT放疗的直肠癌患者45例,依据治疗计划分别创建基于Delta4、EDose和PD系统的验证计划并进行剂量验证。采用Kruskal-Wallis检验比较3种剂量验证系统在3%/3 mm、3%/2 mm、2%/3 mm、2%/2 mm 4种γ评价标准下的绝对剂量的γ通过率。结果 在3%/3 mm的评价标准下,Delta4、EDose和PD系统的平均γ通过率分别为99.90%、98.34%和98.60%。在3%/3 mm、3%/2 mm、2%/3 mm的评价标准下,3种验证系统的平均γ通过率均>95%,满足临床要求。3种剂量验证系统在4种评价标准下的γ通过率比较,差异有统计学意义(P<0.05)。通过进一步两两比较发现,Delta4系统的γ通过率高于EDose系统和PD系统,差异有统计学意义(P <0.05);EDose系统和PD系统的γ通过率比较,差异无统计学意义(P>0.05)。结论 Delta4系统的γ通过率优于EDose系统和PD系统,PD系统的γ通过率和EDose系统相近。Delta4系统、EDose系统和PD系统均可用于直肠癌VMAT计划的剂量验证中。由于EDose系统和PD系统在保证验证精度的同时,摆位简单、使用方便、验证效率高,在临床应用中可以优先考虑。Delta4系统严格的剂量验证γ评价标准可以采用2%/2 mm,EDose系统和PD系统严格的剂量验证γ评价标准可以采用3%/2 mm或2%/3 mm。

Objective To compare and analyze the dose validation results of Delta4,EDose,and Portal Dosimetery(PD)dose validation systems in the volumetric modulated arc therapy(VMAT)plan for rectal cancer and select appropriate validation methods and evaluation criteria for dose validation.Methods With retrospective selection of 45 patients with rectal cancer who received VMAT radiotherapy in the Department of Radiotherapy,the Union Hospital Affiliated to Fujian Medical University,the validation plans based on Delta4,EDose,and PD systems were created according to the treatment plans,and dose validation was performed.The Kruskal-Wallis test was used to compare theγpassing rates of absolute dose for the three dose-validation systems in the four γ evaluation criteria with 3%/3 mm,3%/2 mm,2%/3 mm,and 2%/2 mm.Results With the evaluation criteria of 3%/3 mm,the averageγpassing rates of Delta4,EDose,and PD systems were 99.90%,98.34%,and 98.60%,respectively.With the evaluation criteria of 3%/3 mm,3%/2 mm and 2%/3 mm,the averageγpassing rate of the three validation systems was>95%,which met the clinical requirements.Theγpassing rates of the three dose-validation systems with the four evaluation criteria were compared,and the differences were statistically significant(P<0.05).Through further pairwise comparison,it was found that theγpassing rate of Delta4 system was higher than that of EDose system and PD system,and the differences were statistically significant(P<0.05);There was no significant difference inγpassing rate between EDose system and PD system(P>0.05).Conclusions The Delta4 system has a betterγpassing rate than the EDose system and the PD system,and the PD system has a similarγpassing rate to the EDose system.The Delta4 system,the EDose system and the PD system can all be used for dose validation of the VMAT plan for rectal cancer.With the validation accuracy ensured,the EDose system and PD system has simple positioning,convenient use,and high validation efficiency,which can be prioritized in clinical applications.2%/2 mm can be used as a rigorous dose-validation gamma evaluation criterion for the Delta4 system,3%/2 mm or 2%/3 mm can be used as strict dose-validationγevaluation criteria for EDose systems and PD systems.