调强适形容积旋转放射治疗全骨髓照射：4DCT 计划和同期加量的可行性剂量学研究。
Dose-escalated volumetric modulated arc therapy for total marrow irradiation: A feasibility dosimetric study with 4DCT planning and simultaneous integrated boost.
机构信息
Radiation Oncology, University Hospital of Geneva, Geneva, Switzerland.
Radiation Oncology, University Hospital of Geneva, Geneva, Switzerland.
出版信息
Phys Med. 2020 Oct;78:123-128. doi: 10.1016/j.ejmp.2020.09.013. Epub 2020 Sep 28.
PURPOSE
To evaluate the planning feasibility of dose-escalated total marrow irradiation (TMI) with simultaneous integrated boost (SIB) to the active bone marrow (ABM) using volumetric modulated arc therapy (VMAT), and to assess the impact of using planning organs at risk (OAR) volumes (PRV) accounting for breathing motion in the optimization.
METHODS
Five patients underwent whole-body CT and thoraco-abdominal 4DCT. A planning target volume (PTV) including all bones and ABM was contoured on each whole-body CT. PRV of selected OAR (liver, heart, kidneys, lungs, spleen, stomach) were determined with 4DCT. Planning consisted of 9-10 full 6 MV photon VMAT arcs. Four plans were created for each patient with 12 Gy prescribed to the PTV, with or without an additional 4 Gy SIB to the ABM. Planning dose constraints were set on the OAR or on the PRV. Planning objective was a PTV D < 110% of the prescribed dose, a PTV V < 50%, and OAR D ≤ 50-60%.
RESULTS
PTV D < 110% was accomplished for most plans (n = 18/20), while all achieved V<50%. SIB plans succeeded to optimally cover the boost volume (median ABM D = 16.3 Gy) and resulted in similar OAR sparing compared to plans without SIB (median OAR D = 40-54% of the ABM prescribed dose). No statistically significant differences between plans optimized with constraints on OAR or PRV were found.
CONCLUSIONS
Adding a 4 Gy SIB to the ABM for TMI is feasible with VMAT technique, and results in OAR sparing similar to plans without SIB. Setting dose constraints on PRV does not impair PTV dosimetric parameters.
目的
评估使用容积调强弧形治疗（VMAT）进行全骨髓调强照射（TMI）与同时整合增敏（SIB）剂量递增治疗活性骨髓（ABM）的计划可行性，并评估在优化中考虑呼吸运动的危及器官（OAR）体积（PRV）的影响。
方法
5 名患者接受全身 CT 和胸腹 4DCT 检查。在每个全身 CT 上勾画包括所有骨骼和 ABM 的计划靶区（PTV）。使用 4DCT 确定选定 OAR（肝、心、肾、肺、脾、胃）的 PRV。计划由 9-10 个全 6 MV 光子 VMAT 弧形组成。为每位患者创建了 4 个计划，每个计划的 12 Gy 处方剂量用于 PTV，或者 PTV 加 4 Gy 的 SIB 剂量用于 ABM。计划剂量限制设置在 OAR 或 PRV 上。计划目标是 PTV D<110%的处方剂量，PTV V<50%，OAR D≤50-60%。
结果
大多数计划（n=18/20）都实现了 PTV D<110%，所有计划都实现了 V<50%。SIB 计划成功地最佳覆盖了增敏体积（ABM D 的中位数为 16.3 Gy），与没有 SIB 的计划相比，结果相似，OAR 保护较好（OAR D 为 ABM 处方剂量的 40-54%）。在 OAR 或 PRV 上进行约束优化的计划之间未发现统计学上的显著差异。
结论
使用 VMAT 技术为 TMI 中 ABM 增加 4 Gy 的 SIB 是可行的，并且与没有 SIB 的计划相比，OAR 保护相似。在 PRV 上设置剂量限制不会损害 PTV 剂量学参数。
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