A 2-D diode array and analysis software for verification of intensity modulated radiation therapy delivery
A 2-D diode array and analysis software for verification of intensity modulated radiation therapy delivery
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DOI：
10.1118/1.1567831
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发表时间：
2003-05-01
期刊：
影响因子：
3.8
通讯作者：
Nelms, BE
中科院分区：
文献类型：
--
作者：
Jursinic, PA;Nelms, BE
对二维二极管阵列进行分析，该阵列可用于测量辐射束在平面中产生的剂量。该测量设备是 MapCHECK(TM) 型号 1175（Sun Nuclear，墨尔本，佛罗里达州）。该器件在 22 X 22 cm(2) 二维阵列中具有可变间距的 445 个 N 型二极管。整个二极管阵列可以轻松校准，以便进行绝对剂量测量。为了保证 IMRT 质量，每个光束均单独测量，光束中心轴垂直于二极管平面。软件可用于对测量值与治疗计划系统计算的剂量分布进行分析比较。差异百分比和一致性距离的比较标准由操作员定义。数据显示，当射束通量变化超过 300 倍时，二极管阵列具有线性响应，这是调强放射治疗 (IMRT) 射束中典型的调制水平。对于交付的监测器单位 100 倍的变化，也显示出线性依赖性。描述了如何在临床中使用该设备来保证 IMRT 领域的质量的方法。通过补偿器和 MLC 调制的典型 IMRT 光束的测量结果与治疗计划系统剂量计算进行了比较。对典型的 IMRT 质量保证测量进行时间分析。二维二极管阵列的设置、校准和分析时间约为 20 分钟，具体取决于场数。这比使用放射胶片进行类似分析所需的时间要少得多。二维二极管阵列非常适合在 IMRT 系统完全调试后按计划进行质量保证。 (C) 2003 年美国医学物理学家协会。
An analysis is made of a two-dimensional array of diodes that can be used for measuring dose generated in a plane by a radiation beam. This measuring device is the MapCHECK(TM) Model 1175 (Sun Nuclear, Melbourne, FL). This device has 445 N-type diodes in a 22 X 22 cm(2) 2-D array with variable spacing. The entire array of diodes is easily calibrated to allow for measurements in absolute dose. For IMRT quality assurance, each beam is measured individually with the beam central axis oriented perpendicular to the plane of diodes. Software is available to do the analytical comparison of measurements versus dose distributions calculated by a treatment planning system. Comparison criteria of percent difference and distance-to-agreement are defined by the operator. Data are presented that show the diode array has linear response when beam fluence changes by over 300-fold, which is typical of the level of modulation in intensity modulated radiation therapy, IMRT, beams. A linear dependence is also shown for a 100-fold change in monitors units delivered. Methods for how this device can be used in the clinic for quality assurance of IMRT fields are described. Measurements of typical IMRT beams that are modulated by compensators and MLCs are presented with comparisons to treatment planning system dose calculations. A time analysis is done for typical IMRT quality assurance measurements. The setup, calibration, and analysis time for the 2-D diode array are on the order of 20 min, depending on numbers of fields. This is significantly less time than required to do similar analysis with radiographic film. The 2-D diode array is ideal for per-plan quality assurance after an IMRT system is fully commissioned. (C) 2003 American Association of Physicists in Medicine.