【摘要】 目的:探讨摆位误差对脑立体定向放疗剂量分布的影响,指导改进定位方案。方法:随机选取10例脑立体定向放疗患者,借助XVI采集患者摆位后治疗前的锥形束CT(CBCT)和放疗后的CBCT,分别与计划CT配准,获得放疗前和放疗中的摆位误差。借助Xio计划系统,研究摆位误差对计划靶区(PTV)的适形度、平均剂量和最大剂量值的影响。结果:脑立体定向放疗前和放疗中的摆位误差分别为(3.40±1.14)和(0.36±0.12)mm。放疗前摆位误差使PTV的相对适形度由1.00±0.00降低为0.81±0.17(P=0.007,t=-3.494),使相对平均剂量改变了1.56%±1.15%(P=0.002,t=4.304)。放疗中摆位误差对PTV剂量分布的影响可忽略。结论:图像引导的无框架脑立体定向放射治疗在线修正摆位误差,可获得较高的几何和剂量测量精度。更多还原

【Abstract】 Objective To investigate the effect of setup errors on dose distribution in intracranial stereotactic radiotherapy(SRT)for improving positioning scheme. Methods Ten patients receiving intracranial SRT was randomly enrolled in the study. The cone beam CT before and after radiotherapy was acquired by XVI and then was registered with planning CT to obtain the setup errors before and during radiotherapy. Moreover, Xio planning system was used to investigate the effects of setup errors on the conformity, mean dose and maximum dose of planning target areas. Results The setup errors before and during intracranial SRT were(3.40±1.14) and(0.36±0.12) mm, respectively. The relative conformity index of planning target areas was reduced from1.00±0.00 to 0.81±0.17(P=0.007, t=-3.494). The relative mean dose was increased by 1.56%±1.15 %(P=0.002, t=4.304). The effect of setup errors during radiotherapy on dose distribution was negligible. Conclusion Using image-guided frameless intracranial SRT with online correction of setup errors can achieve high geometric and dosimetric accuracies.更多还原