有无均整器模式下脊柱转移瘤立体定向放疗计划的剂量学比较

目的 比较 6 MV X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(t=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。

Dosimetric comparison of stereotactic body radiation therapy plans for spine metastasis using flattening filter free and flattening filter modes

Objective 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<0.01), while the treatment time was almost half of the latter (t=17.27, P<0.01). ConclusionsTwo 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.