Department of Functional and Stereotactic Neurosurgery and Gamma Knife Radiosurgery, Timone University Hospital, Aix Marseille Université, Marseille, France.
Inserm, L'Institut de Neurosciences des Systèmes (INS, UMR1106), Aix Marseille Université, Marseille, France.
Stereotact Funct Neurosurg. 2022;100(1):53-60. doi: 10.1159/000519024. Epub 2021 Nov 24.
Radiosurgery has demonstrated good safety and efficacy in the treatment of multiple brain metastases (BMs). However, multi-target dose planning can be challenging and time-consuming. A recently developed real-time inverse treatment planning (IP) by convex optimization has been demonstrated to produce high-quality treatment plans with good conformity and selectivity in single-target plans. We intended to test the capacity of this IP to rapidly generate efficient plans while optimizing the preservation of normal tissue in multiple BM.
Seventy-nine patients (mean age 62.4, age range 22-85) with a total of 272 BMs were treated by Gamma Knife Radiosurgery. All subjects were treated using a forward planning (FP) technique by an expert neurosurgeon. The new Intuitive Plan was applied and able to automatically generate an alternative plan for each patient. All planning variables were collected from the IP to be compared with the corresponding measurements obtained from the FP. A paired sample t test was applied to compare the 2 plans for the following variables: brain volumes receiving 10 Gy (V10) (primary endpoint), and 12 Gy (V12), planning indices (selectivity, coverage, gradient, and Paddick Conformity Index [PCI]), beam-on time (BOT), and integral doses. Additionally, the noninferiority margin for each item was calculated, and the 2 plans were compared for noninferiority using a paired t test.
The mean age of patients was 62.4 years old (age range 22-85), with a sex ratio of 1.02. The average number of lesions per patient was 3.4 (range 1-12). The mean prescription dose was 21.46 Gy (range 14-24 Gy). Noninferiority of the IP was concluded for V10, V12, prescription isodose volume, BOT, PCI, and selectivity. The V10 (and V12) was significantly lower with the IP (p < 0.001). These volumes were 8.69 cm3 ± 11.39 and 5.47 cm3 ± 7.03, respectively, for the FP and 7.57 cm3 ± 9.44 and 4.78 cm3 ± 5.86 for the IP. Only the coverage was significantly lower with the IP (-2.3%, p < 0.001), but both selectivity (+17%) and PCI (+15%) were significantly higher with the IP than FP (p < 0.001).
This IP demonstrated its capacity to generate multi-target plans rapidly, with a dose to the brain (V10) and BOT noninferior to the one of a human expert planner. These results would benefit from confirmation in a larger prospective series.
放射外科治疗多发性脑转移瘤（BM）具有良好的安全性和有效性。然而，多靶剂量规划可能具有挑战性和耗时。最近开发的凸优化实时反治疗计划（IP）已被证明能够在单靶计划中产生高质量的治疗计划，具有良好的适形性和选择性。我们旨在测试该 IP 在优化多个 BM 中正常组织保留的同时，快速生成有效计划的能力。
79 例（平均年龄 62.4 岁，年龄范围 22-85 岁）共 272 个 BM 的患者接受了伽玛刀放射外科治疗。所有患者均由一位神经外科专家采用正向计划（FP）技术进行治疗。新的 Intuitive Plan 被应用并能够为每位患者自动生成替代计划。从 IP 中收集所有规划变量，以与 FP 获得的相应测量值进行比较。采用配对样本 t 检验比较 2 种计划的以下变量：脑体积接受 10 Gy（V10）（主要终点）和 12 Gy（V12）、计划指数（选择性、覆盖度、梯度和 Paddick 适形指数[PCI]）、束流开启时间（BOT）和积分剂量。此外，还计算了每个项目的非劣效性边界，并使用配对 t 检验比较了 2 种计划的非劣效性。
患者的平均年龄为 62.4 岁（年龄范围 22-85 岁），男女比例为 1.02。每位患者的平均病灶数为 3.4（范围 1-12）。平均处方剂量为 21.46 Gy（范围 14-24 Gy）。IP 的 V10、V12、处方等剂量体积、BOT、PCI 和选择性具有非劣效性。V10（和 V12）的 IP 明显低于 FP（p < 0.001）。FP 的 V10 和 V12 分别为 8.69 cm3±11.39 和 5.47 cm3±7.03，IP 为 7.57 cm3±9.44 和 4.78 cm3±5.86。仅覆盖度的 IP 明显低于 FP（-2.3%，p < 0.001），但 IP 的选择性（+17%）和 PCI（+15%）明显高于 FP（p < 0.001）。
该 IP 证明了其快速生成多靶计划的能力，脑剂量（V10）和 BOT 与人类专家规划师的剂量相当。这些结果需要在更大的前瞻性系列中得到证实。
