Agility MLC 运动补偿容积调制弧形治疗的实验评估。
An experimental evaluation of the Agility MLC for motion-compensated VMAT delivery.
机构信息
Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey, SM2 5PT, UK.
出版信息
Phys Med Biol. 2013 Jul 7;58(13):4643-57. doi: 10.1088/0031-9155/58/13/4643.
An algorithm for dynamic multileaf-collimator (dMLC) tracking of a target performing a known a priori, rigid-body motion during volumetric modulated arc therapy (VMAT), has been experimentally validated and applied to investigate the potential of the Agility (Elekta AB, Stockholm, Sweden) multileaf-collimator (MLC) for use in motion-compensated VMAT delivery. For five VMAT patients, dosimetric measurements were performed using the Delta(4) radiation detector (ScandiDos, Uppsala, Sweden) and the accuracy of dMLC tracking was evaluated using a gamma-analysis, with threshold levels of 3% for dose and 3 mm for distance-to-agreement. For a motion trajectory with components in two orthogonal directions, the mean gamma-analysis pass rate without tracking was found to be 58.0%, 59.0% and 60.9% and was increased to 89.1%, 88.3% and 93.1% with MLC tracking, for time periods of motion of 4 s, 6 s and 10 s respectively. Simulations were performed to compare the efficiency of the Agility MLC with the MLCi MLC when used for motion-compensated VMAT delivery for the same treatment plans and motion trajectories. Delivery time increases from a static-tumour to dMLC-tracking VMAT delivery were observed in the range 0%–20% for the Agility, and 0%–57% with the MLCi, indicating that the increased leaf speed of the Agility MLC is beneficial for MLC tracking during lung radiotherapy.
一种针对目标在容积调强弧形治疗（VMAT）期间执行已知刚体运动的动态多叶准直器（dMLC）跟踪的算法已通过实验验证，并应用于研究 Agility（Elekta AB，斯德哥尔摩，瑞典）多叶准直器（MLC）在运动补偿 VMAT 交付中的潜在用途。对于五名 VMAT 患者，使用 Delta(4)辐射探测器（ScandiDos，乌普萨拉，瑞典）进行剂量测量，并使用伽马分析评估 dMLC 跟踪的准确性，剂量阈值为 3%，距离一致性阈值为 3mm。对于具有两个正交方向分量的运动轨迹，无跟踪时的平均伽马分析通过率分别为 58.0%、59.0%和 60.9%，而使用 MLC 跟踪时分别提高到 89.1%、88.3%和 93.1%，运动时间分别为 4s、6s 和 10s。进行了模拟，以比较在相同的治疗计划和运动轨迹下，使用 Agility MLC 和 MLCi MLC 进行运动补偿 VMAT 交付的效率。从静态肿瘤到 dMLC 跟踪 VMAT 交付的输送时间增加，Agility 的范围为 0%–20%，MLCi 的范围为 0%–57%，这表明 Agility MLC 的叶片速度增加有利于肺放疗期间的 MLC 跟踪。
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