ELECTROMAGNETIC REAL-TIME TUMOR POSITION MONITORING AND DYNAMIC MULTILEAF COLLIMATOR TRACKING USING A SIEMENS 160 MLC: GEOMETRIC AND DOSIMETRIC ACCURACY OF AN INTEGRATED SYSTEM
ELECTROMAGNETIC REAL-TIME TUMOR POSITION MONITORING AND DYNAMIC MULTILEAF COLLIMATOR TRACKING USING A SIEMENS 160 MLC: GEOMETRIC AND DOSIMETRIC ACCURACY OF AN INTEGRATED SYSTEM
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DOI：
10.1016/j.ijrobp.2010.03.043
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发表时间：
2011-02-01
影响因子：
7
通讯作者：
Oelfke, Uwe
中科院分区：
文献类型：
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作者：
Krauss, Andreas;Nill, Simeon;Oelfke, Uwe
目的：动态多叶准直器跟踪代表了一种对移动肿瘤进行高精度放射治疗的有前途的方法。在本研究中，我们报告了将电磁实时肿瘤位置监测集成到基于多叶准直器的跟踪系统中。方法和材料：该集成系统在几何和放射学精度方面进行了表征。前者是根据在跟踪模式下将辐射传送到体模期间获取的射野图像来评估的。跟踪误差是根据从射野图像中提取的跟踪场和体模的位置来计算的。放射学准确性是通过对在正弦轨迹上移动的不同体模进行适形和调强放射治疗时进行的胶片剂量测定来评估的。将静态辐射传输到非移动目标，作为传输到移动体模的参考，无论是否应用 I 机架。结果：尽管系统延迟相对较大（500 毫秒），但二维目标运动仍观察到亚毫米跟踪精度。胶片剂量测定几乎完全恢复了圆形剂量分布，并应用了二维跟踪：2%/2 mm 伽马射线失效率可以从 59.7% 降低到 3.3%。对于单束调强放射治疗，精度受到有限叶宽的限制。应用跟踪后，2%/2 mm 伽玛故障率仍为 15.6%。 结论：我们提出的集成系统标志着高精度动态多叶准直器跟踪的临床实施迈出了重要一步。然而，仍然需要解决一些挑战，例如不规则的运动轨迹或彻底的质量保证。 (C) 2011 爱思唯尔公司
Purpose: Dynamic multileaf collimator tracking represents a promising method for high-precision radiotherapy to moving tumors. In the present study, we report on the integration of electromagnetic real-time tumor position monitoring into a multileaf collimator-based tracking system.Methods and Materials: The integrated system was characterized in terms of its geometric and radiologic accuracy. The former was assessed from portal images acquired during radiation delivery to a phantom in tracking mode, The tracking errors were calculated from the positions of the tracking field and of the phantom as extracted from the portal images. Radiologic accuracy was evaluated from film dosimetry performed for conformal and intensity-modulated radiotherapy applied to different phantoms moving on sinusoidal trajectories. A static radiation delivery to the nonmoving target served as a reference for the delivery to the moving phantom with and without I racking applied.Results: Submillimeter tracking accuracy was observed for two-dimensional target motion despite the relatively large system latency of 500 ms. Film dosimetry yielded almost complete recovery of a circular dose distribution with tracking in two dimensions applied: 2%/2 mm gamma-failure rates could be reduced from 59.7% to 3.3%. For single-beam intensity-modulated radiotherapy delivery, accuracy was limited by the finite leaf width. A 2%/2 mm gamma-failure rate of 15.6% remained with tracking applied.Conclusion: The integrated system we have presented marks a major step toward the clinical implementation of high-precision dynamic multileaf collimator tracking. However, several challenges such as irregular motion traces or a thorough quality assurance still need to be addressed. (C) 2011 Elsevier Inc.