Sklifosovsky Research Institute of Emergency Care, Moscow, Russia.
Department of Neurosurgery, Klinikum Rechts der Isar, Technical University Munich, Munich, Germany; and.
J Clin Neurophysiol. 2020 Jan;37(1):50-55. doi: 10.1097/WNP.0000000000000621.
Navigated transcranial magnetic stimulation (nTMS) provides noninvasive visualization of eloquent brain areas. The nTMS is usually applied in presurgical planning to minimize the risk of surgery-related neurological deterioration. The aim of this study was to evaluate the usefulness of nTMS data for GammaKnife treatment planning for patients suffering from brain metastases.
Motor cortex mapping with nTMS was performed in eight patients with brain metastases within or adjacent to the precentral gyrus. The nTMS data set was imported into the planning software and fused with anatomical MRI. Then contouring of the target and critical structures was performed. Treatment plans with and without visualization of the functional structures by nTMS were analyzed and compared by neurosurgeon and medical physicist.
The primary motor cortex was successfully delineated even in all cases despite significant peritumoral edema. Beam shaping and combined isocenters were used for conformal dose distribution and steeper dose fall-off near the identified eloquent zone. Compared with plans without nTMS data, treatment plans with integration of cortical nTMS mapping data showed a 2% to 78% (mean, 35.2% ± 22.7%) lower 12-Gy volume within the motor cortex without reduction of the dose applied to the tumor.
The presented approach allows the easy and reliable integration of neurophysiological mapping data into GammaKnife treatment plans by the standard GammaPlan software. Diminishing the dose to critical structures might help to minimize side effects and therefore improve quality of life for brain metastasis patients.
经颅导航磁刺激（nTMS）可提供语言相关脑区的无创可视化。nTMS 通常应用于术前规划，以最大限度地降低与手术相关的神经功能恶化风险。本研究旨在评估 nTMS 数据在伽玛刀治疗脑转移瘤患者中的应用价值。
对 8 例位于或毗邻中央前回的脑转移瘤患者进行 nTMS 运动皮层映射。将 nTMS 数据集导入规划软件，并与解剖 MRI 融合。然后进行靶区和关键结构的勾画。神经外科医生和医学物理学家分析并比较了有和无 nTMS 功能结构可视化的治疗计划。
即使在存在明显肿瘤周围水肿的情况下，仍能成功勾画初级运动皮层。采用适形束形成和联合等中心点技术，实现靶区适形剂量分布和在确定的语言区附近陡峭的剂量下降。与无 nTMS 数据的计划相比，整合皮质 nTMS 映射数据的治疗计划在不降低肿瘤剂量的情况下，使运动皮层内 12-Gy 体积降低 2%至 78%（平均值为 35.2%±22.7%）。
本研究通过标准的 GammaPlan 软件，实现了将神经生理映射数据轻松、可靠地整合到伽玛刀治疗计划中的方法。降低关键结构的剂量可能有助于减少副作用，从而提高脑转移瘤患者的生活质量。
