Yin G, Koren S, Lin M, Chen L, Ma C
Sichuan Cancer Hospital, ChengDu, Sichuan.
Fox Chase Cancer Center, Philadelphia, PA.
Med Phys. 2012 Jun;39(6Part19):3842. doi: 10.1118/1.4735683.
To evaluate the Volumetric Modulated Arc Therapy (VMAT, RapidArc) and IMRT plan quality for prostate deliveries conducted by two different treatment planning systems: Oncentra Masterplan (Nucletron inc.) and Eclipse (Varian inc.).
We investigated ten prostate treatment delivery plans. For a given case studied we created a RapidArc plan (Eclipse), a VMAT and an IMRT plan (Oncentra) by using both treatment planning systems. The rotational therapy plans consisted of 2 to 3 arcs and the IMRT fields consisted of 7 to 9 fields. The prescription dose was 200 cGy X 40 fx using a Varian Trilogy with 10 MV beams. The treatment parameters were used to evaluate the plan quality: the minimal, mean and maximal doses to the target (PTV) and the volumes received 65Gy and 40 Gy, respectively, for the rectum and bladder, V65 and V40. In addition, we calculated the conformity index (CI) and the heterogeneity index (HI) for each delivery type.
No significant difference was found between RapidArc, VMAT and IMRT, regarding the minimal and average PTV dose value. The rectum and bladder constraints showed no significant variation as well. The PTV hot spot was significantly higher for the VMAT plan compared to the RapidArc plan (p=0.007). The target CI for VMAT (0.55±0.05) and IMRT (0.71±0.08) was found to be smaller than the RapidArc (0.82±0.04) and the difference is statistically significant (p=0). The HI, value was found to have no significant difference between RapidArc, VMAT and IMRT plan deliveries.
Two TPS are capable of producing high-quality treatment plans for prostate cancer. The quality is associated with the degree of intensity modulation and the number of incident angles. Overall, the RapidArc plans with 2-3 arcs showed better dosimetric qualities than the VMAT and IMRT plans.
评估由两种不同治疗计划系统（Oncentra Masterplan，Nucletron公司；Eclipse，Varian公司）执行的前列腺放疗中容积调强弧形治疗（VMAT，快速弧形放疗）和调强放射治疗（IMRT）计划的质量。
我们研究了十个前列腺治疗计划。对于给定的研究病例，我们使用两种治疗计划系统分别创建了一个快速弧形放疗计划（Eclipse）、一个VMAT计划和一个IMRT计划（Oncentra）。旋转治疗计划由2至3个弧形组成，IMRT野由7至9个野组成。处方剂量为200 cGy×40次分割，使用Varian Trilogy直线加速器的10 MV射线束。使用治疗参数评估计划质量：靶区（PTV）的最小、平均和最大剂量，以及直肠和膀胱分别接受65 Gy和40 Gy的体积，即V65和V40。此外，我们计算了每种放疗类型的适形指数（CI）和不均匀性指数（HI）。
在快速弧形放疗、VMAT和IMRT之间，关于最小和平均PTV剂量值未发现显著差异。直肠和膀胱的限制条件也未显示出显著变化。与快速弧形放疗计划相比，VMAT计划的PTV热点显著更高（p = 0.007）。发现VMAT（0.55±0.05）和IMRT（0.71±0.08）的靶区CI小于快速弧形放疗（0.82±0.04），且差异具有统计学意义（p = 0）。在快速弧形放疗、VMAT和IMRT计划放疗之间，HI值未发现显著差异。
两种治疗计划系统都能够为前列腺癌制定高质量的治疗计划。质量与调强程度和入射角数量有关。总体而言，具有2 - 3个弧形的快速弧形放疗计划在剂量学质量上优于VMAT和IMRT计划。
