Huang Yangyang, Yang Jun, Song Rui, Qin Tingting, Yang Menglin, Liu Yibao
School of Nuclear Science and Engineering, East China University of Technology, Nanchang, Jiangxi, China.
Department of Radiotherapy, the Second Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
Front Oncol. 2024 Dec 5;14:1431082. doi: 10.3389/fonc.2024.1431082. eCollection 2024.
Volumetric-modulated arc therapy (VMAT) may have the highest overall performance for stereotactic body radiotherapy (SBRT) treatment of inoperable early-stage NSCLC. However, in centers lacking the VMAT technique, the dynamic conformal arc therapy (DCAT) technique is potentially the best option for small and rounded NSCLC-SBRT. Therefore, we will comprehensively analyze the advantages of the DCAT versus the other techniques except VMAT in terms of dosimetry, plan complexity, delivery time, γ-passing rates and the interplay effect.
36 patients with early-stage centrally located NSCLC with PTV volumes < 65 cc were enrolled. All patients were redesigned with 50Gy/5f, and 100% of the prescribed dose was normalized to cover 95% of the PTV. The other two delivery techniques compared to the DCAT technique include 3-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT), which use the same parameters for all three techniques.
The dosimetric parameters of the 3-group plans all met the RTOG 0813 protocol. Unsurprisingly, plan complexity parameters such as segments and MUs were significantly reduced in the DCAT plans by 159.56 and 925.90 compared to the IMRT plans, respectively (all < 0.001). The delivery time of the DCAT plans was the least of 164.51 s (all < 0.05). Compared to the IMRT plans, the γ-passing rates were higher in the DCAT plans ( < 0.001), with the most significant difference of 6.01% in the (2%, 1 mm) criteria. As for the interplay effect, the mean dose difference (MDD) in the DCAT plans was as good as the 3DCRT plans at different respiratory amplitudes but better than the IMRT plans (all < 0.05), and the MDD of DCAT plans did not exceed 3% in all respiratory amplitude.
In centers lacking the VMAT technique, implementing SBRT treatment based on the DCAT technique for inoperable early-stage centrally-located NSCLC patients with PTV volumes < 65 cc achieves better treatment efficiency and delivery accuracy while maintaining the plan quality.
容积调强弧形放疗（VMAT）在不可手术的早期非小细胞肺癌（NSCLC）立体定向体部放疗（SBRT）中可能具有最高的总体性能。然而，在缺乏VMAT技术的中心，动态适形弧形放疗（DCAT）技术可能是小而圆形NSCLC-SBRT的最佳选择。因此，我们将从剂量学、计划复杂性、照射时间、γ通过率和相互作用效应方面全面分析DCAT与除VMAT之外的其他技术相比的优势。
纳入36例早期中心型NSCLC患者，其计划靶体积（PTV）<65 cc。所有患者重新设计为50Gy/5次分割，规定剂量的100%归一化以覆盖95%的PTV。与DCAT技术相比的另外两种照射技术包括三维适形放疗（3DCRT）和调强放疗（IMRT），这三种技术使用相同的参数。
三组计划的剂量学参数均符合RTOG 0813方案。不出所料，与IMRT计划相比，DCAT计划中的计划复杂性参数（如射野分段数和机器跳数）分别显著减少了159.56和925.90（均<0.001）。DCAT计划的照射时间最短，为164.51秒（均<0.05）。与IMRT计划相比，DCAT计划的γ通过率更高（<0.001），在（2%，1毫米）标准下差异最为显著，为6.01%。至于相互作用效应，在不同呼吸幅度下，DCAT计划的平均剂量差异（MDD）与3DCRT计划相当，但优于IMRT计划（均<0.05），并且DCAT计划在所有呼吸幅度下的MDD均不超过3%。
在缺乏VMAT技术的中心，对于PTV体积<65 cc的不可手术的早期中心型NSCLC患者，基于DCAT技术实施SBRT治疗在保持计划质量的同时，可实现更好的治疗效率和照射精度。
