Varian Medical Systems Inc., Advanced Oncology Solutions, Hixson, Tennessee, USA.
Thompson Cancer Survival Center, Cumberland Medical Center, Crossville, Tennessee, USA.
J Appl Clin Med Phys. 2024 Nov;25(11):e14503. doi: 10.1002/acm2.14503. Epub 2024 Sep 5.
HyperArc (HA) auto-planning offers simplicity for the end user and consistently high-quality SRS plans. The "Ask For It" (AFI) optimization strategy offers a manual planning technique that, when coupled with R50%, can be guided to deliver a plan with an intermediate dose spill "as low as reasonably achievable" and high target dose conformity. A direct comparison of SRS plan quality obtained using the manual planning AFI strategy and HA has been performed.
Using a CT data set available from the Radiosurgery Society, 54 PTVs were created and used to generate 19 individual SRS/SRT cases. Case complexity ranged from single PTV plans to multiple PTV plans with a single isocenter. PTV locations ranged from relative isolation from critical structures to lesions within 1.5 mm of the optic apparatus and abutting the brainstem. All cases were planned using both the AFI and HA optimization strategies as implemented in the Varian Medical Systems Eclipse Treatment Planning System. A range of treatment plan quality metrics were obtained including Intermediate Dose Spill (R50%), Conformity Indices CI and CI, PTV Dose Coverage (Dn%), PTV Mean Dose, and Modulation Factor. The Wilcoxon Signed Rank Sum non-parametric statistical method was utilized to compare the obtained plan quality metrics.
Statistically significant improvements were found for the AFI strategy for metrics R50%, CI, CI, and PTV Mean Dose (p < 0.001). HA achieved superior coverage for Dn% (p = 0.018), while the Modulation Factors were not significantly different for AFI compared to HA optimization (p = 0.13).
This study provides evidence that the AFI manual planning strategy can produce high-quality planning metrics similar to the HA auto-planning method.
HyperArc（HA）自动规划为最终用户提供了简单性，并始终提供高质量的 SRS 计划。“要求（Ask For It，AFI）”优化策略提供了一种手动规划技术，当与 R50%结合使用时，可以指导生成具有中间剂量泄漏“尽可能低”和高靶剂量一致性的计划。已经对使用手动规划 AFI 策略和 HA 获得的 SRS 计划质量进行了直接比较。
使用放射外科协会提供的 CT 数据集，创建了 54 个 PTV 并用于生成 19 个单独的 SRS/SRT 病例。病例的复杂性从单个 PTV 计划到具有单个等中心点的多个 PTV 计划不等。PTV 的位置从与关键结构相对隔离到距视器 1.5 毫米以内的病变，与脑干相邻。所有病例均使用 AFI 和 HA 优化策略在 Varian Medical Systems Eclipse 治疗计划系统中进行规划。获得了一系列治疗计划质量指标，包括中间剂量泄漏（R50%）、适形性指数 CI 和 CI、PTV 剂量覆盖率（Dn%）、PTV 平均剂量和调制因子。使用 Wilcoxon 符号秩和非参数统计方法比较获得的计划质量指标。
对于 R50%、CI、CI 和 PTV 平均剂量等指标，AFI 策略有统计学上的显著改善（p < 0.001）。HA 实现了 Dn%的卓越覆盖（p = 0.018），而与 HA 优化相比，AFI 的调制因子没有显著差异（p = 0.13）。
这项研究提供了证据，证明 AFI 手动规划策略可以产生类似于 HA 自动规划方法的高质量规划指标。
