摘要
目的:探究Eclipse计划系统中自动正常组织目标(NTO)工具在宫颈癌术后辅助放疗的容积旋转调强放疗(VMAT)计划设计中的最优权重,为宫颈癌VMAT计划设计提供科学依据。方法:回顾性选取2023年7月~12月在福建省肿瘤医院接受放疗的20例宫颈癌根治性术后患者,使用自动NTO优先级权重分别为20、40、60、80、100、120、150和200,为每例患者分别重新制定8个VMAT计划,另外设置一计划组关闭自动NTO功能并手动做限量环与自动NTO计划组进行比较。处方剂量覆盖计划靶区的95%体积以上,统计每个计划的靶区适形度指数(CI)、均匀性指数(HI)、剂量梯度指数(GI)、机器跳数、危及器官(OAR)受照剂量和计划指标参数等数据。检验不同权重计划之间CI和HI的差异,找到最优权重。结果:随着NTO权重的增加,靶区内冷热点均呈增长趋势。在NTO权重为20和40时,靶区外易出现热点;而当权重增至200时,靶区内易形成热点。同时,OAR剂量随NTO权重增加而降低,显示出保护OAR的趋势。从HI指数来看,随着NTO权重的增加,靶区剂量均匀性下降,尤其在权重为120至200时更为明显。CI值则随权重增加而提高,表明靶区适形性得到改善。GI指数显示当NTO权重设置越高靶区外剂量下降越迅速。因此,本研究推荐宫颈癌VMAT计划中自动NTO的最佳权重值为80~100。结论:通过综合分析剂量热点、CI、HI和GI等关键参数,确定宫颈癌术后辅助放疗计划设计中自动NTO的最优权重范围,这一权重设置能够有效平衡靶区覆盖和OAR保护的剂量需求,为临床计划设计提供参考。
Objective To investigate the optimal weight of the normal tissue objective(NTO)tool in the Eclipse treatment planning system for volumetric modulated arc therapy(VMAT)plans in postoperative adjuvant radiotherapy for cervical cancer,thereby providing a scientific basis for VMAT planning for cervical cancer.Methods A retrospective analysis was conducted on 20 cervical cancer patients who underwent radical surgery and received radiotherapy at Fujian Cancer Hospital between July and December 2023.For each patient,8 VMAT plans were regenerated using automatic NTO priority weights of 20,40,60,80,100,120,150,and 200,respectively,and then compared with a traditional ring-shaped constraint plan which was established as the control group by deactivating the automatic NTO function.The prescription dose covered at least 95%of the planning target volume.Dosimetric parameters including conformity index(CI),homogeneity index(HI),and gradient index(GI),machine units(MU),and organs at risk(OAR)doses were evaluated for all plans.Differences in CI and HI across plans with varying NTO weights were analyzed to determine the optimal weight value.Results As the NTO weight increased,both cold and hot spots within the target area showed an increasing trend.At NTO weights of 20 and 40,hot spots were more prone to occur outside the target area,while at a weight increasing to 200,hot spots tended to form within the target area.Meanwhile,OAR doses decreased with higher NTO weights,indicating improved OAR sparing efficacy.Regarding HI,dose homogeneity within the target area deteriorated as the NTO weight increased,especially at weights of 120 and 200.Conversely,CI value improved with increasing NTO weight,reflecting enhanced target conformity.GI value demonstrated a steeper dose fall-off outside the target area at higher NTO weights.Based on these findings,the optimal NTO weight range for cervical cancer VMAT plans was determined to be 80-100.Conclusion Through comprehensive analysis of critical dosimetric parameters including dose hotspots,CI,HI,and GI,the optimal NTO weight range for postoperative adjuvant radiotherapy planning in cervical cancer is identified.This weight range can effectively balance target area coverage and OAR sparing,providing guidance for clinical VMAT planning.
作者
丘贺金
孔燕
杨扬
林家帆
陈开强
李晓静
QIU Hejin;KONG Yan;YANG Yang;LIN Jiafan;CHEN Kaiqiang;LI Xiaojing(Clinical Oncology School of Fujian Medical University,Fujian Cancer Hospital,Fuzhou 350014,China;Department of Radiation Oncology,Affiliated Hospital of Jiangnan University,Wuxi 214122,China)
出处
《中国医学物理学杂志》
2025年第12期1548-1555,共8页
Chinese Journal of Medical Physics
基金
国家自然科学基金青年项目(12205120)
无锡市“太湖人才计划”医疗卫生高层次人才项目
无锡市双百人才项目(HB2023059)
无锡市转化医学研究所项目(LCYJ202339)
福建省卫生健康科技项目(2023GGA053)。
关键词
宫颈癌
容积旋转调强放疗
自动正常组织目标
剂量学
cervical cancer
volumetric modulated arc therapy
automatic normal tissue objective
dosimetry
