Narayanasamy Ganesh, Shrestha Nishan, Bimali Milan, Xia Fen, Su Zhong
Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of BioStatistics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
J Appl Clin Med Phys. 2025 Jul;26(7):e70115. doi: 10.1002/acm2.70115. Epub 2025 Jun 12.
To generate high-quality stereotactic radiosurgery (SRS) plans for single cranial lesions using 4Pi planning technique and compare these to our clinical "status quo" plans.
Eighteen vestibular schwannoma (VS) patients previously planned with Varian Eclipse RapidArc and treated on a Varian TrueBeam using 6FFF MV photon beams were randomly selected. This cohort was replanned in Brainlab Elements Cranial SRS using an automatic 4Pi trajectory optimization technique ("Elements 4Pi"). "Elements ArcMatch" plans were also created, which utilized the identical arc geometry as the clinical plans in Eclipse, that is, used identical table angles, gantry start and stop angles, and collimator angles to isolate the inherent differences between the two treatment planning systems. SRS plan evaluation metrics included the Inverse Paddick conformity index (IPCI), gradient index (GI), max doses to the brainstem and ipsilateral cochlea, and number of monitor units (MUs). Pairwise comparisons between Eclipse and Elements 4Pi plans were performed using Wilcoxon signed rank test. For three-way comparisons with Elements-ArcMatch plans, the difference in distribution of SRS metrics was assessed first based on Friedman's test, followed by pairwise comparison if the findings from Friedman's test met statistical significance. A two-sided p-value of 0.05 was used to determine statistical significance.
While both Elements 4Pi and Elements ArcMatch plans had significantly lower GI, MU, and max doses to the brainstem and ipsilateral cochlea compared to Eclipse plans (p-values < 0.05), Elements 4Pi also had significantly lower IPCI values.
The automation in Brainlab Elements Cranial SRS outperformed manual expert planning and produced collision-free and clinically deliverable plans for single targets with significantly better dose conformality, dose gradient, and lower dose to normal organs while using lower MUs compared to clinically delivered Eclipse plans.
使用4Pi计划技术为单个颅脑病变生成高质量的立体定向放射外科（SRS）计划，并将其与我们临床的“现状”计划进行比较。
随机选择18例先前使用瓦里安Eclipse RapidArc计划并在瓦里安TrueBeam上使用6FFF MV光子束进行治疗的前庭神经鞘瘤（VS）患者。该队列在Brainlab Elements Cranial SRS中使用自动4Pi轨迹优化技术（“Elements 4Pi”）重新计划。还创建了“Elements ArcMatch”计划，该计划使用与Eclipse临床计划相同的弧形几何形状，即使用相同的床角度、机架起始和停止角度以及准直器角度，以隔离两个治疗计划系统之间的固有差异。SRS计划评估指标包括反向帕迪克适形指数（IPCI）、梯度指数（GI）、脑干和同侧耳蜗的最大剂量以及监测单位（MU）数量。使用Wilcoxon符号秩检验对Eclipse和Elements 4Pi计划进行成对比较。对于与Elements-ArcMatch计划的三向比较，首先基于Friedman检验评估SRS指标分布的差异，如果Friedman检验的结果具有统计学意义，则进行成对比较。使用双侧p值0.05来确定统计学意义。
与Eclipse计划相比，Elements 4Pi和Elements ArcMatch计划的GI、MU以及脑干和同侧耳蜗的最大剂量均显著降低（p值<0.05），Elements 4Pi的IPCI值也显著更低。
Brainlab Elements Cranial SRS中的自动化优于手动专家计划，为单个靶区生成了无碰撞且临床可交付的计划，与临床交付的Eclipse计划相比，剂量适形性、剂量梯度显著更好，对正常器官的剂量更低，同时使用的MU更少。
