Clemente S, Cozzolino M, Oliviero C, Fiorentino A, Chiumento C, Fusco V
Department of Radiation Oncology, IRCCS CROB, Via Padre Pio n.1, 85028, Rionero in Vulture, PZ, Italy,
Clin Transl Oncol. 2014 Feb;16(2):141-6. doi: 10.1007/s12094-013-1049-6. Epub 2013 May 4.
To evaluate the impact of different machines on plan quality using both intensity modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) techniques.
Eight patients with squamous cell carcinoma of the oropharynx were selected at random. Plans were computed for IMRT and VMAT Smart Arc, using Pinnacle TPS for an Elekta (IMRT-E, VMAT-E) and Varian linac (IMRT-V, VMAT-V). A three-dose level prescription was used to deliver 70, 63 and 58.1 Gy to regions of macroscopic, microscopic high- and low-risk disease, respectively. All doses were given in 35 fractions. Comparisons were performed on dose-volume histogram data, monitor units (MU), and delivery time.
VMAT-E plans resulted slightly MU efficient (-24 % p < 0.05) compared to VMAT-V while IMRT-V shortened delivery time (-19 % p < 0.05) compared to IMRT-E. All the delivery techniques resulted in equivalent target coverage in terms of D(98) % and D(2) %. For VMAT technique, a significant improvement of 7 % in homogeneity index (HI) for PTV58.1 was observed for Varian machine. A slight improvement in OARs sparing was observed with Elekta machine both for IMRT and VMAT techniques.
Similar plan quality was observed for Elekta and Varian linacs, significant differences were observed in delivery efficiency, as MU number and delivery times, in favor of Elekta and Varian, respectively.
使用调强放射治疗（IMRT）和容积调强弧形治疗（VMAT）技术评估不同机器对计划质量的影响。
随机选择8例口咽鳞状细胞癌患者。使用Pinnacle治疗计划系统针对医科达直线加速器（IMRT-E、VMAT-E）和瓦里安直线加速器（IMRT-V、VMAT-V）计算IMRT和VMAT Smart Arc计划。采用三剂量水平处方，分别向大体肿瘤、微小高危和低危疾病区域给予70、63和58.1 Gy的剂量。所有剂量均分35次给予。对剂量体积直方图数据、监测单位（MU）和照射时间进行比较。
与VMAT-V相比，VMAT-E计划的MU效率略高（-24%，p<0.05）；与IMRT-E相比，IMRT-V缩短了照射时间（-19%，p<0.05）。所有照射技术在D(98)%和D(2)%方面均能实现等效的靶区覆盖。对于VMAT技术，使用瓦里安机器时，PTV58.1的均匀性指数（HI）显著提高了7%。使用医科达机器时，无论是IMRT还是VMAT技术，在危及器官保护方面均有轻微改善。
医科达和瓦里安直线加速器的计划质量相似，但在照射效率方面存在显著差异，分别有利于医科达和瓦里安，具体体现在MU数量和照射时间上。
