胶质母细胞瘤术后IMRT和VMAT的剂量学比较

发布时间：2018-08-23 10:32

【摘要】：目的比较胶质母细胞瘤术后放疗采用逆向调强(IMRT)和容积旋转调强(VMAT)技术在靶区和危及器官的剂量学差异,并比较不同技术的机器跳数、计划优化时间和治疗时间的差异,探讨VMAT技术在胶质母细胞瘤放疗中应用的可行性和优劣性。方法收集胶质母细胞瘤病例资料10例,术后3周内行MR增强扫描及CT增强定位扫描,层厚3 mm,采用医科达的Oncentra治疗计划系统进行MR-CT图像融合,医生勾画靶区和危及器官;物理师对个病例分别设计5野的IMRT计划、单弧VMAT计划(VMAT1)和双弧VMAT计划(VMAT2),处方剂量为PTV 60 Gy/30f。利用剂量体积直方图(DVH)和等剂量分布曲线比较靶区的覆盖率、适形指数、均匀指数以及危及器官的受照剂量,比较不同技术的机器跳数、优化时间和治疗时间的差异。结果 3组计划靶区剂量分布均较好,IMRT、VMAT1和VMAT2的靶区PTV 95%体积达到的剂量组间比较差异无统计学意义;适形指数组间差异有统计学意义,VMAT的适形指数比IMRT好,但单弧VMAT与双弧VMAT两组间差异无统计学意义。均匀指数3组间差异无统计学意义。危及器官包括脑干、患侧晶体、对侧晶体、患侧视神经、对侧视神经和视交叉,所有危及器官的最高剂量在3组计划中差异均无统计学意义。机器跳数3组间差异有统计学意义,IMRT组与VMAT1组比VMAT2组的跳数少。治疗时间3组间差异有统计学意义,IMRT组与VMAT1组比VMAT2组的治疗时间少,VMAT1组治疗时间最短。计算优化的时间IMRT最短,双弧VMAT最长,3组计划差异均有统计学意义。结论胶质母细胞瘤术后放疗计划设计采用单、双弧的VMAT计划的靶区适型指数都好于IMRT组。单弧的VMAT计划的机器跳数与IMRT计划相当,但治疗时间短。双弧的VMAT计划的机器跳数多、治疗时间长。计算优化的时间IMRT短,VMAT长。
[Abstract]:Objective to compare the difference of dosimetry between (IMRT) and (VMAT) in target area and organ danger after postoperative radiotherapy for glioblastoma, and to compare the difference of machine hopping, planning optimization time and treatment time between different techniques. To investigate the feasibility and advantages of VMAT technique in radiotherapy of glioblastoma. Methods the data of 10 cases of glioblastoma were collected. Three weeks after operation, Mr enhanced scan and CT enhanced localization scan with slice thickness of 3 mm were performed. The MR-CT images were fused with the Oncentra treatment plan system, and the target area and the dangerous organs were delineated by doctors. Physicians designed a 5-field IMRT program, a single-arc VMAT program (VMAT1) and a double-arc VMAT program (VMAT2) for each case. The prescription dose was PTV 60 Gy / 30 f. Dose volume histogram (DVH) and isodose distribution curve were used to compare target coverage, conformal index, uniformity index and radiation dose, and to compare the difference of machine hopping, optimization time and treatment time between different techniques. Results there was no significant difference in dose distribution between IMRT VMAT1 and PTV 95% volume of VMAT2, but there was significant difference between conformal index group and IMRT group. But there was no significant difference between the two groups in single arc VMAT and double arc VMAT. There was no significant difference in uniform index among three groups. The organs at risk included brain stem, affected lens, contralateral lens, affected optic nerve, contralateral optic nerve and optic chiasma. There was no significant difference in the maximum dose of all the endangered organs in the three groups. There were statistically significant differences in the number of machine hops among the three groups. The number of hops in IMRT group and VMAT1 group was lower than that in VMAT2 group. There was significant difference in treatment time among the three groups. The treatment time of IMRT group and VMAT1 group was shorter than that of VMAT2 group. The time of calculation and optimization of IMRT was the shortest, and the difference of the three groups of double arc VMAT was statistically significant. Conclusion the target fitness index of single and double arc VMAT plan is better than that of IMRT group. The single-arc VMAT program has about the same number of machine hops as the IMRT plan, but the treatment time is short. Double-arc VMAT program has many machine hops and long treatment time. Calculate the optimized time IMRT short VMAT long.
【作者单位】：暨南大学第二临床医学院深圳市人民医院放疗科;
【基金】：深圳市卫生计生系统科研项目(编号:201401012) 深圳市科技计划项目(编号:JCYJ20150403102020235)
【分类号】：R739.41

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