Examination of conversion method of dose distribution of lung cancer IMRT using fluence reversible calculation function in O-ring type linac and C-type linac.
Examination of conversion method of dose distribution of lung cancer IMRT using fluence reversible calculation function in O-ring type linac and C-type linac.
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DOI：
10.1007/s13246-022-01122-6
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发表时间：
2022-06
影响因子：
4.4
通讯作者：
Togo, Haruki
中科院分区：
文献类型：
--
作者：
Rachi, Toshiya;Parshuram, Raturi Vijay;Tanaka, Yuki;Togo, Haruki
一般来说，当直线加速器发生故障时，可以在 C 臂直线加速器 (C-linac) 之间转换照射计划，而无需使用治疗计划系统 (TPS) 重新计算剂量分布，因为它们具有相似的机械结构。然而，O型环型直线加速器（O-直线加速器）在形成剂量分布方面与C型直线加速器不同。因此，如果O-linac发生故障，需要从头开始制定治疗方案。在本研究中，我们研究了一种将辐射从 O 直线加速器转换为 C 直线加速器的方法。本研究纳入了 30 名肺癌患者，他们接受了 O-linac 容量调节弧形治疗。通过TPS的作用，O-直线加速器剂量分布被转换成能量注量。然后优化替代直线加速器多叶准直器 (MLC) 以实现能量注量。将转换后的计划的均匀性指数、符合性指数、计划治疗量（D95%、D2%）与原计划进行比较。对于危及器官（OAR），评估了肺、食道、心脏和脊髓的剂量体积直方图（DVH）。此外，使用 Dice 相似系数 (DSC) 比较等剂量曲线的形状。目标和 OAR 之间没有显着差异 (p>0.05)。处方剂量的30%至100%等剂量曲线和等剂量 ≥ 105%和 ≤ 20%的平均DSC分别为 > 0.8和 < 0.8。由于MLC的结构差异，在 ≥ 105%和 ≤ 20%的剂量范围内，剂量体积和生成位置有所不同；因此，DSC 减少。然而，两种治疗计划的 DVH 均未发现统计学上的显着差异。基于这一结果，我们提出了一种简单的重新规划方法，用于在将剂量转换为能量注量后执行 MLC 拟合。
Generally, converting irradiation plans between C-arm linacs (C-linac) when the linac fails is possible without recalculating the dose distribution using a treatment planning system (TPS), because they have similar mechanical structure. However, the O-ring-type linac (O-linac) differs from the C-linac in forming the dose distribution. Therefore, if O-linac breaks down, it is necessary to formulate a treatment plan from scratch. In this study, we investigated a method for converting irradiation from an O-linac to a C-linac. Thirty patients with lung cancer who underwent volumetric-modulated arc therapy with an O-linac were included in this study. The O-linac dose distribution was converted into energy fluence by the function of the TPS. The alternative linac multi-leaf collimator (MLC) was then optimized to achieve energy fluence. The homogeneity index, conformity index, and planning treatment volume (D95%, D2%) of the converted plan were compared with the original plan. For organ at risk (OAR), the dose-volume histograms (DVHs) of the lung, esophagus, heart, and spinal cord were evaluated. Additionally, the shapes of the isodose curves were compared using the Dice similarity coefficient (DSC). There was no significant difference between the target and OARs (p > 0.05). The mean DSCs of 30% to 100% isodose curves of the prescribed dose and the isodose ≥ 105% and ≤ 20%were > 0.8 and < 0.8, respectively. Due to the structural differences of MLC, the dose-volume and generation positions were different in the dose range of ≥ 105% and ≤ 20%; hence, DSCs decreased. However, no statistically significant difference in the DVH was identified for either treatment plan. Based on this result, we propose a simple replanning method for performing MLC fitting after converting the dose to the energy fluence.
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影响因子：
3.8
作者：
Miften, Moyed;Olch, Arthur;Low, Daniel A.
通讯作者：
Low, Daniel A.
影响因子：
3.8
作者：
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影响因子：
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影响因子：
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通讯作者：
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