直线加速器不同出束模式对鼻咽癌容积旋转调强放疗计划的影响  

Effect of Different Beam Mode of Linear Accelerator on VMAT Plans for Radiotherapy of Nasopharyngeal Carcinoma

作　　者：谭军文 龙雨松[1] 贺先桃 李钢 冯永富 梁卫学[1] 王占宇[1] TAN Junwen;LONG Yusong;HE Xiantao;LI Gang;FENG Yongfu;LIANG Weixue;WANG Zhanyu(Department of Oncology,Liuzhou Worker’s Hospital,Liuzhou Guangxi 545005,China)

机构地区：[1]柳州市工人医院肿瘤科,广西柳州545005

出　　处：《中国医疗设备》2023年第10期56-61,共6页China Medical Devices

基　　金：广西卫健委自筹经费科研课题(Z20200966);广西重点研发计划(桂科AB22035026);柳州市科技计划项目(2022SB011)。

摘　　要：目的研究直线加速器不同出束模式下鼻咽癌容积旋转调强放疗(Volume Modulated Arc Therapy,VMAT)计划的剂量学差异,为鼻咽癌VMAT中最佳出束模式的选择提供参考。方法选取我院收治的10例鼻咽癌患者采用相同的处方剂量和计划参数设计6 MV X射线均整模式(Flattening Filter,FF)下的6X VMAT计划、6 MV X射线非均整模式(Flattening Filter Free,FFF)下的6 FFF VMAT计划以及10 MV X射线FF下的10X VMAT计划,比较3种计划的剂量学特性。结果3种计划在靶区剂量上差异较小,且均能达到处方剂量要求。6 FFF VMAT计划在部分评估指标上略差于6X VMAT计划和10X VMAT计划,PTV_(5115)的_(Dmean),6 FFF VMAT计划高于6X VMAT计划和10X VMAT计划;计划靶区(Planning Target Volume,PTV_(6417))的D_(mean)、D_(2%),6 FFF VMAT计划大于6X VMAT计划;PTV_(6603)的D_(98%),6 FFF VMAT计划小于6X VMAT计划;PTV_(6975)的D_(mean),6 FFF VMAT计划大于6X VMAT计划,差异均有统计学意义(P<0.05)。靶区剂量的其他指标以及靶区覆盖率比较,3种计划的差异均无统计学意义(P>0.05)。在危及器官保护方面的优势排序依次为6 FFF VMAT计划>10X VMAT计划>6X VMAT计划。6FFF VMAT计划相比10X VMAT计划和6X VMAT计划在保护皮肤和正常组织方面具有一定的优势,且10X VMAT计划又优于6X VMAT。6 FFF VMAT计划、10X VMAT计划的机器跳数显著高于6X VMAT计划(P<0.05)。结论6X、6 FFF和10X这3种模式下的鼻咽癌VMAT计划均能满足临床要求且各有特点,其中6 FFF VMAT计划与10X VMAT计划、6X VMAT计划相比在危及器官和正常组织保护方面更有优势;10X VMAT计划与6X VMAT计划相比在靶区及危及器官保护方面水平相当。从计划优化角度,为降低危及器官受照剂量,推荐采用6 FFF下的VMAT计划。Objective To study the dosimetric differences of volume modulated arc therapy(VMAT)plans for nasopharyngeal carcinoma in different beam mode of linear accelerator,and to provide reference for the selection of the best beam mode in nasopharyngeal carcinoma VMAT radiotherapy.Methods A total of 10 patients with nasopharyngeal carcinoma admitted to our hospital were selected to design 6 X VMAT plan under 6 MV X-ray flattening filter(FF)mode,6 FFF VMAT plan under 6 MV X-ray flattening filter free(FFF)mode and 10 X VMAT plan under 10 MV X-ray FF mode with the same prescription dose and plan parameters.The dosimetric characteristics of the three plans were compared.Results The three plans had little difference in target dose and could meet the prescription dose requirement.The 6 FFF VMAT plan was slightly inferior to the 6X VMAT plan and 10X VMAT plan in a few evaluation indicators,and on the D_(mean) of PTV_(5115),the 6 FFF VMAT plan was higher than the 6X VMAT plan and 10X VMAT plan;On the D_(mean) and D_(2%) of PTV_(6417),the 6 FFF VMAT plan was higher than the 6X VMAT plan.At D_(98%) of PTV_(6603),the 6 FFF VMAT plan was lower than the 6X VMAT plan.On the D_(mean) of PTV_(6975),the 6FFF VMAT plan was higher than the 6X VMAT plan,the differences were statistically significant(P<0.05).Compared with other target dose indicators and target coverage,there was no significant difference among the three plans(P>0.05).The advantages in the protection of endangered organs were ranked as 6 FFF VMAT plan>10X VMAT plan>6X VMAT plan.6 FFF VMAT plan had certain advantages over 10X VMAT plan and 6X VMAT plan in protecting skin and normal tissue,and 10X VMAT plan was superior to 6X VMAT plan.The monitor units in 6 FFF VMAT plan and 10X VMAT plan was significantly higher than that in 6X VMAT plan(P<0.05).Conclusion The VMAT plan of 6X,6 FFF and 10X can meet the clinical requirements and have their own characteristics.Compared with 10X VMAT and 6X VMAT plan,the 6 FFF VMAT plan has more advantages in the protection of endangered organs

关 键 词：鼻咽癌 出束模式 容积旋转调强放疗 直线加速器 危及器官 

分 类 号：R144[医药卫生—公共卫生与预防医学] R815.2