Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA.
Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA.
J Appl Clin Med Phys. 2020 Jul;21(7):209-215. doi: 10.1002/acm2.12893. Epub 2020 May 8.
Prior in silico simulations propose that Temporally Feathered Radiation Therapy (TFRT) may reduce toxicity related to head and neck radiation therapy. In this study we demonstrate a step-by-step guide to TFRT planning with modern treatment planning systems.
One patient with oropharyngeal cancer planned for definitive radiation therapy using intensity-modulated radiation therapy (IMRT) techniques was replanned using the TFRT technique. Five organs at risk (OAR) were identified to be feathered. A "base plan" was first created based on desired planning target volumes (PTV) coverage, plan conformality, and OAR constraints. The base plan was then re-optimized by modifying planning objectives, to generate five subplans. All beams from each subplan were imported onto one trial to create the composite TFRT plan. The composite TFRT plan was directly compared with the non-TFRT IMRT plan. During plan assessment, the composite TFRT was first evaluated followed by each subplan to meet preset compliance criteria.
The following organs were feathered: oral cavity, right submandibular gland, left submandibular gland, supraglottis, and OAR Pharynx. Prescription dose PTV coverage (>95%) was met in each subplan and the composite TFRT plan. Expected small variations in dose were observed among the plans. The percent variation between the high fractional dose and average low fractional dose was 29%, 28%, 24%, 19%, and 10% for the oral cavity, right submandibular, left submandibular, supraglottis, and OAR pharynx nonoverlapping with the PTV.
Temporally Feathered Radiation Therapy planning is possible with modern treatment planning systems. Modest dosimetric changes are observed with TFRT planning compared with non-TFRT IMRT planning. We await the results of the current prospective trial to seeking to demonstrate the feasibility of TFRT in the modern clinical workflow (NCT03768856). Further studies will be required to demonstrate the potential benefit of TFRT over non-TFRT IMRT Planning.
先前的计算机模拟表明，时间羽毛状放射治疗（TFRT）可能会降低头颈部放射治疗相关的毒性。在这项研究中，我们展示了使用现代治疗计划系统进行 TFRT 计划的逐步指南。
对一名接受适形调强放射治疗（IMRT）技术治疗的口咽癌患者进行了重新计划，使用 TFRT 技术进行了重新计划。确定了五个需要羽毛状的危及器官（OAR）。首先根据所需的计划靶区（PTV）覆盖、计划适形度和 OAR 约束创建“基础计划”。然后通过修改计划目标重新优化基础计划，生成五个子计划。从每个子计划中导入所有光束到一个试验中，以创建复合 TFRT 计划。直接比较复合 TFRT 计划和非 TFRT IMRT 计划。在计划评估期间，首先评估复合 TFRT，然后评估每个子计划以满足预设的合规标准。
对以下器官进行了羽毛状处理：口腔、右侧下颌下腺、左侧下颌下腺、会厌和声门上区 OAR。每个子计划和复合 TFRT 计划均满足处方剂量 PTV 覆盖（>95%）。在计划中观察到预期的剂量小变化。高分次剂量与平均低分次剂量之间的百分比变化为口腔、右侧下颌下腺、左侧下颌下腺、会厌和声门上区 OAR 非 PTV 重叠的 29%、28%、24%、19%和 10%。
现代治疗计划系统可以进行时间羽毛状放射治疗计划。与非 TFRT IMRT 计划相比，TFRT 计划观察到适度的剂量学变化。我们正在等待当前前瞻性试验的结果，以寻求证明 TFRT 在现代临床工作流程中的可行性（NCT03768856）。需要进一步的研究来证明 TFRT 相对于非 TFRT IMRT 计划的潜在益处。
