Comparison of dose calculation algorithms for treatment planning in external photon beam therapy for clinical situations
Comparison of dose calculation algorithms for treatment planning in external photon beam therapy for clinical situations
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DOI：
10.1088/0031-9155/51/22/005
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发表时间：
2006-11-21
影响因子：
3.5
通讯作者：
Lassen, Soren
中科院分区：
文献类型：
--
作者：
Knoos, Tommy;Wieslander, Elinore;Lassen, Soren
研究了五种商业放射治疗计划系统（TPS）对常见治疗部位的异质性和散射光子建模能力的性能。比较是基于前列腺癌、头颈癌、乳腺癌和肺癌病例的CT信息。TPS安装在当地不同的机构，并根据当地程序委托临床使用。为了进行评价，使用尽可能相同的射束质量：低能（6 MV）和高能（15或18 MV）X射线。所有相关的解剖结构进行了概述，并建立了简单的治疗计划。使用DICOM协议将图像、结构和计划导出、匿名化并分发给参与机构。然后，这些计划在当地重新计算，并导出进行评估。TPS涵盖了从基于校正的等效路径长度算法到基于模型的算法的剂量计算技术。根据如何考虑电子传递的变化，将其分为两组（（a）未考虑和（B）考虑）。从相对均匀的骨盆区域到非常不均匀的肺部区域，增加复杂性导致剂量分布不太准确。当模型考虑体积散射和电子输运的变化时，特别是当照射体积的延伸受到限制时，以及当低密度存在于场中或附近时，已显示出计算剂量的改进。一个Monte Carlo计算算法的输入数据集和一个虚拟直线加速器的基准集已经产生，这有利于分析和解释的结果。类型B组中更复杂的模型表现出吸收剂量及其分布的变化，这与基于蒙特卡罗的虚拟加速器进行的模拟一致。
A study of the performance of five commercial radiotherapy treatment planning systems ( TPSs) for common treatment sites regarding their ability to model heterogeneities and scattered photons has been performed. The comparison was based on CT information for prostate, head and neck, breast and lung cancer cases. The TPSs were installed locally at different institutions and commissioned for clinical use based on local procedures. For the evaluation, beam qualities as identical as possible were used: low energy ( 6 MV) and high energy ( 15 or 18 MV) x-rays. All relevant anatomical structures were outlined and simple treatment plans were set up. Images, structures and plans were exported, anonymized and distributed to the participating institutions using the DICOM protocol. The plans were then re-calculated locally and exported back for evaluation. The TPSs cover dose calculation techniques from correction-based equivalent path length algorithms to model-based algorithms. These were divided into two groups based on how changes in electron transport are accounted for (( a) not considered and ( b) considered). Increasing the complexity from the relatively homogeneous pelvic region to the very inhomogeneous lung region resulted in less accurate dose distributions. Improvements in the calculated dose have been shown when models consider volume scatter and changes in electron transport, especially when the extension of the irradiated volume was limited and when low densities were present in or adjacent to the fields. A Monte Carlo calculated algorithm input data set and a benchmark set for a virtual linear accelerator have been produced which have facilitated the analysis and interpretation of the results. The more sophisticated models in the type b group exhibit changes in both absorbed dose and its distribution which are congruent with the simulations performed by Monte Carlo-based virtual accelerator.