Supplementary Material for: The Brain Connectome after Gamma Knife Radiosurgery of the Ventro-Intermediate Nucleus for Tremor: Marseille-Lausanne Radiobiology Study Protocol

Essential tremor (ET) is the most common movement disorder. Deep brain stimulation is the current gold standard for drug-resistant tremor, followed by radiofrequency lesioning. Stereotactic radiosurgery by Gamma Knife (GK) is considered as a minimally invasive alternative. The majority of procedures aim at the same target, thalamic ventro-intermediate nucleus (Vim). The primary aim is to assess the clinical response in relationship to neuroimaging changes, both at structural and functional level. All GK treatments are uniformly performed in our center using Guiot’s targeting and a radiation dose of 130 Gy. MR neuroimaging protocol includes structural imaging (T1-weighted and diffusion-weighted imaging [DWI]), resting-state functional MRI, and 18F-fluorodeoxyglucose-positron emission tomography. Neuroimaging changes are studied both at the level of the cerebello-thalamo-cortical tract (using the prior hypothesis based upon Vim’s circuitry: motor cortex, ipsilateral Vim, and contralateral cerebellar dentate nucleus) and also at global brain level (no prior hypothesis). This protocol aims at using modern neuroimaging techniques for studying Vim GK radiobiology for tremor, in relationship to clinical effects, particularly in ET patients. In perspective, using such an approach, patient selection could be based upon a specific brain connectome profile.

特发性震颤（Essential Tremor, ET）是最常见的运动障碍性疾病。目前，药物难治性震颤的标准治疗方案为脑深部电刺激术，次选方案为射频毁损术。伽玛刀（Gamma Knife, GK）立体定向放射外科则被视为该领域的微创替代治疗手段。此类手术的绝大多数均以丘脑腹中间核（thalamic ventro-intermediate nucleus, Vim）作为共同靶点。本研究的首要目标为评估临床疗效与神经影像学变化的关联，后者同时覆盖结构与功能两个层面。本中心开展的所有伽玛刀治疗均统一采用吉奥靶向技术，辐射剂量统一设置为130 Gy。本次研究的磁共振神经影像学扫描方案包括：结构成像（T1加权成像与弥散加权成像[DWI]）、静息态功能磁共振成像，以及18F-氟代脱氧葡萄糖正电子发射断层扫描。研究将从两个维度解析神经影像学变化：其一为小脑-丘脑-皮质通路（基于Vim核的神经环路提出先验假设，涉及运动皮层、同侧Vim核及对侧小脑齿状核）；其二为全脑层面（无预先假设）。本研究方案旨在借助现代神经影像学技术，探究Vim核伽玛刀放射外科治疗的放射生物学特征及其与临床疗效的关联，尤其针对特发性震颤患者展开分析。从远期展望来看，通过该研究路径，可基于特定脑连接组特征实现患者的精准筛选。