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首页> 外文期刊>Radiotherapy and oncology: Journal of the European Society for Therapeutic Radiology and Oncology >Evaluation of margining algorithms in commercial treatment planning systems.
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Evaluation of margining algorithms in commercial treatment planning systems.

机译：商业治疗计划系统中保证金算法的评估。

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INTRODUCTION: During commissioning of the Pinnacle (Philips) treatment planning system (TPS) the margining algorithm was investigated and was found to produce larger PTVs than Plato (Nucletron) for identical GTVs. Subsequent comparison of PTV volumes resulting from the QA outlining exercise for the CHHIP (Conventional or Hypofractionated High Dose IMRT for Prostate Ca.) trial confirmed that there were differences in TPS's margining algorithms. Margining and the clinical impact of the different PTVs in seven different planning and virtual simulation systems (Pinnacle, Plato, Prosoma (MedCom), Eclipse (7.3 and 7.5) (Varian), MasterPlan (Nucletron), Xio (CMS) and Advantage Windows (AW) (GE)) is investigated, and a simple test for 3D margining consistency is proposed. METHODS: Using each TPS, two different sets of prostate GTVs on 2.5mm and 5mm slices were margined according to the CHHIP protocol to produce PTV3 (prostate+5 mm/0 mm post), PTV2 (PTV3+5 mm) and PTV1 (prostate and seminal vesicles+10 mm). GTVs and PTVs were imported into Pinnacle for volume calculation. DVHs for 5mm slice plans, created using the smallest PTVs, were recalculated on the largest PTV dataset and vice versa. Since adding a margin of 50 mm to a structure should give the same result as adding five margins of 10 mm, this was tested for each TPS (consistency test) using an octahedron as the GTV and CT datasets with 2.5 mm and 5 mm slices. RESULTS: The CHHIP PTV3 and PTV1 volumes had a standard deviation, across the seven systems, of 5% and PTV2 (margined twice) 9%, on the 5 mm slices. For 2.5 mm slices the standard deviations were 4% and 6%. The ratio of the Pinnacle and the Eclipse 7.3 PTV2 volumes was 1.25. Rectal doses were significantly increased when encompassing Pinnacle PTVs (V(50)=42.8%), compared to Eclipse 7.3 PTVs (V(50)=36.4%). Conversely, fields that adequately treated an Eclipse 7.3 PTV2 were inadequate for a Pinnacle PTV2. AW and Plato PTV volumes were the most consistent (0.3%) and (-0.4%). However, the 1x50mm margin in Pinnacle produced a 15.9% larger volume than 5 x 10 mm margins, while for Eclipse 7.3 the single margined volume was 14.3% smaller. These inconsistencies were reduced to approximately 5% by adjusting the superior/inferior margins. CONCLUSIONS: Accurate margin algorithms are necessary to ensure that volume expansion does not add extra uncertainty to the radiotherapy planning process. We have found significant differences in the 3D margining algorithms of TPSs, devised a simple test to predict inconsistency and suggested corrective action to minimise the variation.
机译：简介：在品尼高（Philips）治疗计划系统（TPS）调试期间，对保证金算法进行了研究，发现对于相同的GTV，该算法比Plato（Nucletron）产生更大的PTV。随后比较了CHHIP（针对前列腺的常规或低剂量大剂量IMRT）的QA概述活动所产生的PTV量，证实了TPS的保证金算法存在差异。在七个不同的计划和虚拟仿真系统（Pinnacle，Plato，Prosoma（MedCom），Eclipse（7.3和7.5）（Varian），MasterPlan（Nucletron），Xio（CMS）和Advantage Windows（对AW）（GE））进行了研究，并提出了3D页边距一致性的简单测试。方法：使用每个TPS，根据CHHIP协议在2.5mm和5mm切片上切开两组不同的前列腺GTV，以产生PTV3（前列腺+ 5mm / 0mm柱），PTV2（PTV3 + 5mm）和PTV1（前列腺）和精囊+10毫米）。将GTV和PTV导入Pinnacle进行体积计算。使用最小的PTV创建的5mm切片计划的DVH在最大的PTV数据集上重新计算，反之亦然。由于在结构上添加50毫米的空白应该与添加五个10毫米的空白具有相同的结果，因此使用八面体作为2.5毫米和5毫米切片的GTV和CT数据集，对每个TPS（一致性测试）进行了测试。结果：在5毫米的切片上，CHHIP PTV3和PTV1的体积在七个系统中的标准偏差分别为5％和PTV2（两次裕度）为9％。对于2.5毫米的切片，标准偏差为4％和6％。 Pinnacle和Eclipse 7.3 PTV2体积的比率为1.25。与Eclipse 7.3 PTV（V（50）= 36.4％）相比，包围Pinnacle PTV时直肠剂量显着增加（V（50）= 42.8％）。相反，充分处理Eclipse 7.3 PTV2的场对于Pinnacle PTV2是不够的。 AW和柏拉图PTV量最一致（0.3％）和（-0.4％）。但是，Pinnacle中1x50mm的边距比5 x 10mm的边距产生了15.9％的体积，而对于Eclipse 7.3，单个边距的体积减小了14.3％。通过调整上/下边距，可以将这些不一致性降低到大约5％。结论：精确的余量算法是必要的，以确保体积扩展不会给放射治疗计划过程增加额外的不确定性。我们发现TPS的3D边缘算法存在显着差异，设计了一种简单的测试来预测不一致情况，并提出了纠正措施以最大程度地减少变化。

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