Radiation Physics Center, Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan Province, PR China.
Radiat Oncol. 2011 Oct 21;6:140. doi: 10.1186/1748-717X-6-140.
To analyze the differences between the intensity-modulated radiotherapy (IMRT), single/partial-arc volumetric modulated arc therapy (SA/PA-VMAT) techniques in treatment planning for locally advanced lung cancer.
12 patients were retrospectively studied. In each patient's case, several parameters were analyzed based on the dose-volume histograms (DVH) of the IMRT, SA/PA-VMAT plans respectively. Also, each plan was delivered to a phantom for time comparison.
The SA-VMAT plans showed the superior target dose coverage, although the minimum/mean/maximum doses to the target were similar. For the total and contralateral lungs, the higher V5/10, lower V20/30 and mean lung dose (MLD) were observed in the SA/PA-VMAT plans (p < 0.05, respectively). The PA-VMAT technique improves the dose sparing (V20, V30 and MLD) of the controlateral lung more notably, comparing to those parameters of the IMRT and SA-VMAT plans respectively. The delivered monitor units (MUs) and treatment times were reduced significantly with VMAT plans, especially PA-VMAT plans (for MUs: mean 458.3 vs. 439.2 vs. 435.7 MUs, p < 0.05 and for treatment time: mean 13.7 vs. 10.6 vs. 6.4 minutes, p < 0.01).
The SA-VMAT technique achieves highly conformal dose distribution to the target. Comparing to the IMRT plans, the higher V5/10, lower V20/30 and MLD were observed in the total and contralateral lungs in the VMAT plans, especially in the PA-VMAT plans. The SA/PA-VMAT plans also reduced treatment time with more efficient dose delivering. But the clinical benefit of the VMAT technique for locally advanced lung cancer needs further investigations.
分析局部晚期肺癌调强放疗（IMRT）、单/部分弧容积旋转调强放疗（SA/PA-VMAT）技术在治疗计划中的差异。
回顾性研究了 12 例患者。在每位患者的病例中，根据 IMRT、SA/PA-VMAT 计划的剂量体积直方图（DVH）分别分析了几个参数。同时，将每个计划传输到一个体模进行时间比较。
SA-VMAT 计划显示出更好的靶区剂量覆盖，尽管靶区的最小/平均/最大剂量相似。对于全肺和对侧肺，SA/PA-VMAT 计划中观察到更高的 V5/10、更低的 V20/30 和平均肺剂量（MLD）（p < 0.05）。PA-VMAT 技术与 IMRT 和 SA-VMAT 计划相比，更显著地改善了对侧肺的剂量节省（V20、V30 和 MLD）。VMAT 计划显著减少了递送的监控单位（MU）和治疗时间，特别是 PA-VMAT 计划（MU：平均 458.3 对 439.2 对 435.7 MU，p < 0.05；治疗时间：平均 13.7 对 10.6 对 6.4 分钟，p < 0.01）。
SA-VMAT 技术实现了对靶区高度适形的剂量分布。与 IMRT 计划相比，VMAT 计划中观察到全肺和对侧肺的更高的 V5/10、更低的 V20/30 和 MLD，特别是在 PA-VMAT 计划中。SA/PA-VMAT 计划还通过更有效的剂量传递减少了治疗时间。但是，VMAT 技术在局部晚期肺癌中的临床获益需要进一步研究。
