Tatsumi Daisaku, Nakada Ryosei, Yomoda Akane, Ishii Kentaro, Tsutsumi Shinichi, Inoue Makoto, Ichida Takao, Hosono Masako N, Miki Yukio
Department of Radiology, Osaka City University Hospital, 1-5-7 Asahimachi, Abenoku, Osaka 545-8586, Japan.
Radiol Phys Technol. 2013 Jan;6(1):98-106. doi: 10.1007/s12194-012-0175-0. Epub 2012 Aug 14.
We have proposed minimum requirements for commissioning and long-term quality assurance (QA) of an Elekta multi-leaf collimator (MLC) for volumetric modulated arc therapy (VMAT). The MLC leaf position accuracy during VMAT delivery was evaluated with the use of three different QA test plans: (1) a leaf gap-width test between opposing leaves by measurement of the isocenter dose during constant-gap sliding-window delivery with varied dose rates, MLC leaf speeds, and gantry angles; (2) a leaf position test by picket-fence delivery with and without gantry rotation; and (3) a leaf-bank symmetry test by measurement of the field geometry with different collimator angles at a fixed gantry position. All the QA test plans were created using an ERGO++ treatment-planning system. The leaf gap-width deviation was within 0.2 mm, the leaf position deviation was within 0.5 mm, and the leaf-bank symmetry error was within 0.5 mm under all the test conditions. MLC leaf position accuracy and long-term stability were confirmed by the proposed procedures.
我们已经提出了针对医科达容积调强弧形治疗（VMAT）多叶准直器（MLC）的调试及长期质量保证（QA）的最低要求。在VMAT治疗过程中，使用三种不同的QA测试计划对MLC叶片位置精度进行了评估：（1）通过在不同剂量率、MLC叶片速度和机架角度下进行恒定间隙滑动窗口照射时测量等中心剂量，对相对叶片之间的叶片间隙宽度进行测试；（2）通过在有和没有机架旋转的情况下进行栅栏式照射来进行叶片位置测试；（3）通过在固定机架位置测量不同准直器角度下的射野几何形状来进行叶片组对称性测试。所有QA测试计划均使用ERGO++治疗计划系统创建。在所有测试条件下，叶片间隙宽度偏差在0.2毫米以内，叶片位置偏差在0.5毫米以内，叶片组对称误差在0.5毫米以内。所提出的程序证实了MLC叶片位置精度和长期稳定性。
