基于三维动脉自旋标记的剂量引导适形放疗在非增强性低级别胶质瘤中的应用。
Three-dimensional arterial spin labeling-guided dose painting radiotherapy for non-enhancing low-grade gliomas.
机构信息
Department of Oncology, Affiliated Hospital of Southwest Medical University, No.25 Taiping Street, Jiangyang District, Luzhou, 646000, Sichuan, China.
Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, No.440 Jiyan Road, Huaiyin District, Jinan, 250117, Shandong, China.
出版信息
Jpn J Radiol. 2023 Mar;41(3):335-346. doi: 10.1007/s11604-022-01357-z. Epub 2022 Nov 7.
PURPOSE
To investigate the feasibility and dosimetric characteristics of dose painting for non-enhancing low-grade gliomas (NE-LGGs) guided by three-dimensional arterial spin labeling (3D-ASL).
MATERIALS AND METHODS
Eighteen patients with NE-LGGs were enrolled. 3D-ASL, T2 fluid-attenuated inversion recovery (T2 Flair) and contrast-enhanced T1-weighted magnetic resonance images were obtained. The gross tumor volume (GTV) was delineated on the T2 Flair. The hyper-perfusion region of the GTV (GTV-ASL) was determined by 3D-ASL, and the GTV-SUB was obtained by subtracting the GTV-ASL from the GTV. The clinical target volume (CTV) was created by iso-tropically expanding the GTV by 1 cm. The planning target volume (PTV), PTV-ASL were obtained by expanding the external margins of the CTV, GTV-ASL, respectively. PTV-SUB was generated by subtracting PTV-ASL from PTV. Three plans were generated for each patient: a conventional plan (plan 1) without dose escalation delivering 95-110% of 45-60 Gy in 1.8-2 Gy fractions to the PTV and two dose-painting plans (plan 2 and plan 3) with dose escalating by 10-20% (range, 50-72 Gy) to the PTV-ASL based on plan 1. The plan 3 was obtained from plan 2 without the maximum dose constraint. The dosimetric differences among the three plans were compared.
RESULTS
The volume ratio of the PTV-ASL to the PTV was (23.49 ± 11.94)% (Z = - 3.724, P = 0.000). Compared with plan 1, D, D and D of PTV-ASL increased by 14.67%,16.17% and 14.31% in plan2 and 19.84%,15.52% and 14.27% in plan3, respectively (P < 0.05); the D of the PTV and PTV-SUB increased by 11.89% and 8.34% in plan 2, 15.89% and 8.49% in plan 3, respectively (P < 0.05). The PTV coverages were comparable among the three plans (P > 0.05). In plan 2 and plan 3, the conformity indexes decreased by 18.60% and 12.79%; while the homogeneity index increased by 1.43 and 2 times (P < 0.05). Compared with plan 1, the D of brain stem and D of optic chiasma were slightly increased in plan 2 and plan 3, and the absolute doses met the dose constraint. The doses of the other organs at risk (OARs) were similar among the three plans (P > 0.05).
CONCLUSION
The dose delivered to hyper-perfusion volume derived from 3D-ASL can increased by 10-20% while respecting the constraints to the OARs for NE-LGGs, which provides a basis for future individualized and precise radiotherapy, especially if the contrast agent cannot be injected or when contrast enhancement is uncertain.
目的
探讨基于三维动脉自旋标记（3D-ASL）的剂量绘画在非增强性低级别胶质瘤（NE-LGG）中的可行性和剂量学特征。
材料和方法
纳入 18 例 NE-LGG 患者。获取 3D-ASL、T2 液体衰减反转恢复（T2 Flair）和对比增强 T1 加权磁共振图像。在 T2 Flair 上勾画大体肿瘤体积（GTV）。通过 3D-ASL 确定 GTV 的高灌注区（GTV-ASL），并从 GTV 中减去 GTV-ASL 得到 GTV-SUB。通过等距扩展 GTV 1cm 得到临床靶区（CTV）。计划靶区（PTV）、PTV-ASL 分别通过 CTV、GTV-ASL 的外扩得到。PTV-SUB 通过从 PTV 中减去 PTV-ASL 得到。为每位患者生成了 3 种计划：一种是不进行剂量递增的常规计划（计划 1），将 45-60Gy 的 1.8-2Gy 剂量递送至 PTV 的 95-110%；两种是剂量递增计划 2 和计划 3，将 PTV-ASL 的剂量递增 10-20%（范围 50-72Gy），基于计划 1。计划 3 是从没有最大剂量限制的计划 2 中获得的。比较了三种计划之间的剂量差异。
结果
PTV-ASL 与 PTV 的体积比为（23.49±11.94）%（Z=-3.724，P=0.000）。与计划 1 相比，计划 2 和计划 3 中 PTV-ASL 的 D、D 和 D 分别增加了 14.67%、16.17%和 14.31%，19.84%、15.52%和 14.27%（P<0.05）；PTV 和 PTV-SUB 的 D 分别增加了 11.89%和 8.34%，15.89%和 8.49%（P<0.05）。三种计划的 PTV 覆盖率相当（P>0.05）。在计划 2 和计划 3 中，适形指数分别降低了 18.60%和 12.79%；而均匀性指数分别增加了 1.43 和 2 倍（P<0.05）。与计划 1 相比，脑干和视交叉的 D 在计划 2 和计划 3 中略有增加，且绝对剂量符合剂量限制。三种计划中其他危及器官（OARs）的剂量相似（P>0.05）。
结论
对于 NE-LGG，可以在不增加 OAR 剂量限制的情况下，将来自 3D-ASL 的高灌注体积的剂量增加 10-20%，为个体化和精确放疗提供了依据，尤其是在无法注射造影剂或增强不确定时。
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