摘要目的 比较6MVX射线无均整器模式(FFF)和均整器模式(FF)下,脊柱转移瘤立体定向放疗(SBRT)计划的剂量学差异.方法 选取9例入组患者共12处脊柱转移灶分别设计FFF-SBRT和FF-SBRT计划,比较两组计划的靶区、危及器官和正常组织剂量体积直方图(DVH)、靶区适形度(CI)、机器跳数和治疗时间的差别.结果 两种模式下的计划均能满足临床治疗需要.靶区、危及器官、正常组织剂量分布相似.FFF-SBRT计划的机器跳数明显高于FF-SBRT计划(t=-5.20,P＜0.01),实际治疗时间相当于FF-SBRT计划的1/2(=17.27,P＜0.01).结论 两种模式均能满足临床治疗需求,FFF-SBRT计划的治疗时间更短,效率更高.临床试验注册 中国临床试验注册中心,ChiCTR-TRC-14004281.

abstractsObjective To compare the dosimetric difference of stereotactic body radiation therapy (SBRT) plans for spine metastasis using 6 MV X-ray flattening filter free (FFF) and flattening filter (FF) modes.Methods A total of nine previously treated patients with a total of twelve spine metastasis were retrospectively included and replanned using FFF-SBRT and FF-SBRT, respectively.The dose-volume histograms (DVH), target conformity index (CI), monitor unites (MUs) and treatment time of target volume, organs at risk and normal tissues were compared between the plans.Results Both FFF-SBRT and FF-SBRT met the clinical objectives.Dose distribution of target volume, organs at risk and normal tissues were similar.MUs of the FFF-SBRT were significantly higher than that of FF-SBRT (t =-5.20, P ＜0.0l), while the treatment time was almost half of the latter (t =17.27, P ＜ 0.01).Conclusions Two plan modes are both clinically acceptable.FFF-SBRT plans are delivered in less time and with better efficiency.Trial registration Chinese clinical trial registry, ChiCTR-TRC-14004281.