目的 探讨容积调强（VMAT）在全脊柱骨多发转移瘤放疗中的运用,观察疗效及安全性。方法 选取 2018年1月—2021年1月本科室收治的50例全脊柱骨多发转移瘤姑息止痛放疗的临床资料,分别对全脊柱靶区设计适形放疗（CRT）和VMAT多中心计划,运用剂量体积直方图及所对应的统计表评估靶区及危及器官剂量覆盖情况,放疗结束后通过1-8周视觉模拟评分法评价近期疗效,每3个月复查全脊柱MRI观察放疗不良反应。结果 采用VMAT技术放疗靶区剂量覆盖度、靶区适形指数和剂量均匀指数均优于CRT技术（P<0.01）,照射野重叠区未见明显剂量热点和冷点。采用VMAT技术危及器官V5 Gy受照体积高于CRT（P<0.01）,除了胃、胰腺和小肠,危及器官V10 Gy受照体积高于CRT（P<0.01或P<0.05）,危及器官V20 Gy受照体积则低于CRT（P<0.01）,除了肾,危及器官V30 Gy受照体积也低于CRT（P<0.01）。采用VMAT技术时危及器官的最大受照量低于CRT（P<0.01或P<0.05）,但除了心脏、胰腺和小肠,VMAT技术的危及器官平均受照量高于CRT（P<0.01或P<0.05）。采用VMAT技术较CRT出束时间增加（P<0.01）,采用CRT时技师摆位时间较VMAT增加（P<0.05）,对于总治疗时间VMAT较CRT增加（P<0.01）。8周后评估疼痛完全缓解16例,部分缓解 22例,轻度缓解8例,无效4例,总有效率为76%。随访日期截至2021年 12月,所有配合随诊的患者3、6、9、12个月全脊柱MRI复查结果显示,VMAT技术照射野内重叠处均未见脊髓及其他组织急慢性损伤情况。结论 VMAT技术对长靶区多中心放疗剂量分布均匀,近期疗效显著,安全性良好。

Objective To investigate the application of volumetric modulated arc therapy（VMAT） in the radiotherapy for multiple bone metastases in the whole spine,and observe of efficacy and evaluation of safety．Methods The clinical data were selected from 50 patients who were treated in our department between January 2018 and January 2021 with palliative analgesic radiotherapy for multiple metastases of the whole spine．Conformal radiotherapy（CRT）and multicenter VMAT plans were respectively applied to target areas of whole spine,and dose volume histogram was used to evaluate the dose coverage of target area and organ at risk（OAR）. After radiotherapy,the short-term efficacy was evaluated by visual analog scale in between 1-8 weeks,and the whole spine MRI was reviewed every 3 months to observe the adverse reactions of radiotherapy．Results The dose coverage,target conformality index and homogeneity index of VMAT treatment were significantly better than those of CRT treatment（P<0.01）,and no obvious dose hotspots and cold spots were observed in the overlapping area of irradiation field. When VMAT treatment was applied,the exposure volume of V5 Gy in OAR was significantly higher when compared with CRT treatment（P<0.01）．Except for stomach,pancreas and small intestine,the exposure volume of V10 Gy in OAR was significantly higher for VMAT treatment when compared with CRT treatment （P<0.01 or P<0.05）．When VMAT treatment was applied,the exposure volume of V20 Gy in OAR was significantly lower when compared with CRT treatment（P<0.01）,and except for kidney,the exposure volume of V30 Gy in OAR was significantly lower when compared with CRT treatment（P<0.01）．When VMAT treatment was applied,the maximum exposure of OAR was significantly lower than that of CRT（P<0.01 or P<0.05）,however,except for the heart,pancreas and small intestine,the average exposure of VMAT treatment to OAR was higher than that of CRT （P<0.01 or P<0.05）．Compared with CRT,VMAT treatment had significantly increased beam-out time（P<0.01）,the therapist setting time of CRT was increased when compared with that of VMAT（P<0.05）,and the total treatment time of VMAT was increased when compared with that of CRT（P<0.01）. In the assessment 8 weeks after the treatments,16 patients had complete pain relief,22 had partial relief,8 had mild relief,and 4 had no effect,which total effective rate was 76%．The follow-up was ended in December 2021．There was no acute or chronic injury to the spinal cord and other tissues in the overlapping areas of the irradiation fields observed for all follow-up patients in the 3rd,6th,9th and 12th month whole-spine MRI re-examination．Conclusions VMAT has uniform dose distribution in multi-center radiotherapy for long target areas,with significant short-term efficacy and safety.