Accuracy of out-of-field dose calculations by a commercial treatment planning system.
Accuracy of out-of-field dose calculations by a commercial treatment planning system.
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DOI：
10.1088/0031-9155/55/23/s03
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发表时间：
2010-12-07
影响因子：
3.5
通讯作者：
Yaldo DZ
中科院分区：
文献类型：
--
作者：
Howell RM;Scarboro SB;Kry SF;Yaldo DZ
对于治疗场边界之外的位置，治疗计划系统 (TPS) 的剂量测定精度会降低。然而，治疗场边界以外位置的特定 TPS 的真实准确性尚未得到充分记录。我们的目标是量化商用 Eclipse 版本 8.6 TPS（瓦里安医疗系统，加利福尼亚州帕洛阿尔托）在 Varian Clinac 2100 上进行的临床治疗所预测的场外剂量的准确性。我们计算（在 TPS 中）并确定（使用热释光剂量计）总共 238 个测量点的剂量（距场边缘的距离范围为 3.75 至 11.25） 厘米）。我们的比较确定，在检查的距离范围内，Eclipse TPS 平均低估了场外剂量 40%。随着距治疗场距离的增加，TPS 低估剂量的幅度不断增大，在距治疗场边界 11.25 厘米处高达 55%。这些数据证实，超出处理边界的准确性是不够的，只有在清楚了解这一限制的情况下才应使用 TPS 的外场数据。需要精确的场外剂量的研究应使用其他剂量重建方法，例如直接测量或蒙特卡罗计算。
The dosimetric accuracy of treatment planning systems (TPSs) decreases for locations outside the treatment field borders. However, the true accuracy of specific TPSs for locations beyond the treatment field borders is not well documented. Our objective was to quantify the accuracy of out-of-field dose predicted by the commercially available Eclipse version 8.6 TPS (Varian Medical Systems, Palo Alto, CA) for a clinical treatment delivered on a Varian Clinac 2100. We calculated (in the TPS) and determined (with thermoluminescent dosimeters) doses at a total of 238 points of measurement (with distance from the field edge ranging from 3.75 to 11.25 cm). Our comparisons determined that the Eclipse TPS underestimated out-of-field doses by an average of 40% over the range of distances examined. As the distance from the treatment field increased, the TPS underestimated the dose with increasing magnitude—up to 55% at 11.25 cm from the treatment field border. These data confirm that accuracy beyond the treatment border is inadequate, and out-of-field data from TPSs should be used only with a clear understanding of this limitation. Studies that require accurate out-of-field dose should use other dose reconstruction methods, such as direct measurements or Monte Carlo calculations.