Motor Eloquent Navigated Transcranial Magnetic Stimulation for Radiosurgery Planning
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 30
- 试验地点
- 2
- 主要终点
- Within-patient difference in maximum dose
研究概览
简要总结
With this project, the study group wants to investigate whether a postoperative navigated transcranial magnetic stimulation (nTMS) motor map can improve stereotactic radiosurgery (SRS) planning in patients who underwent resection for a brain metastasis near the primary motor cortex. Specifically, the map could allow for more precise location of motor eloquent tissue, thereby minimizing the radiation dose on these areas while preserving high radiation dose on target tissue (i.e. tumor cells).
详细描述
Background:
Radiation therapy is a cornerstone in the management of metastatic brain tumors. It is applied either as a first-line treatment or postoperatively to the resected tumor bed. Delivering a sufficiently high radiation dose to the lesion or tumor bed while preventing neurological deficits due to radionecrosis from overexposure of vulnerable healthy brain tissue remains particularly challenging in eloquent brain regions such as the motor cortex.
According to international guidelines (ICRU Reports 50, 62, and 83), target volumes for radiation therapy must be carefully defined, while organs at risk (OARs), including the optic apparatus, cochlea, hippocampus, brainstem, and pituitary gland, must be spared. The motor cortex (M1) and corticospinal tract (CST) should likewise be preserved; however, they are not formally defined as OARs in current guidelines, and their precise delineation is technically demanding.
The anatomical precentral gyrus ("anatomical M1") does not exactly correspond to the functional location of motor control ("functional M1"). Conventional imaging techniques such as functional MRI (fMRI) and diffusion tensor imaging (DTI) provide limited spatial accuracy, with localization errors of up to 1 cm. In contrast, navigated transcranial magnetic stimulation (nTMS) is a noninvasive method that identifies motor-eloquent regions based on individual MRI data, offering more accurate functional mapping for radiation treatment planning. This raises the question of whether integrating postoperative, pre-radiotherapy nTMS maps could enable more tailored and precise radiation therapy plans.
Previous studies have shown that nTMS demonstrates a median deviation of only 5.2 mm compared with direct cortical stimulation (the gold standard), whereas fMRI may deviate even more than 1 cm. Especially in patients with tumors involving the motor cortex, nTMS has been shown to provide superior spatial accuracy. Preliminary data further suggest that incorporating nTMS into radiotherapy planning may reduce radiation exposure to the motor cortex and CST while maintaining optimal target coverage.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Prevention
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Informed consent
- •Age ≥ 18 years
- •Cerebral metastasis within or adjacent to the primary motor cortex (≤10 mm)
- •Resection of tumor
- •Eligible for and planned to undergo postresection radiosurgery at Inselspital Bern
排除标准
- •Contraindication to TMS (e.g. Cochlear Implant, other metallic or electrical implants, excluding teeth and post craniotomy, Meniere's disease, pacemaker, deep brain stimulation electrodes, refractory convulsion, symptomatic tinnitus, depression diagnosed by a specialist, psychosis)
- •Prior cerebral radiation therapy within the affected precentral gyrus/affecting the planned SRS plan
- •Planned whole brain radiotherapy
- •Second lesion within 2 cm ipsilateral in the primary motor cortex
- •Infection or difficulties in wound healing within the last two weeks prior inclusion
研究组 & 干预措施
MENTOR
Every patient will undergo a postoperative nTMS motor mapping, and both the "standard" and "nTMS-adapted" SRS plan will be created for every patient. The plan will be selected by the radiation oncologist, depending on whether at least 95% of the dose is administered to the target volume with the "nTMS-adapted" plan or not. Every patient then receives SRS.
干预措施: Navigated Transcranial Magnetic Stimulation (nTMS) (Device)
结局指标
主要结局
Within-patient difference in maximum dose
时间窗: 5 to 2 days before SRS
Within-patient difference in maximum dose (defined as the dose received by the most exposed 0.03 cc of the tissue) to functional M1 between the standard and nTMS-adapted SRS plans, provided that both plans achieve PTV coverage ≥95% and comply with standard organ-at-risk constraints
Maximal radiation dose (Gray)
时间窗: 5 to 2 days before SRS
Maximal radiation dose (Gray) on "functional M1" of each radiotherapy plan (standard and nTMS-adapted); functional M1 is defined by patient specific post-surgical nTMS motor-maps
次要结局
- Feasibility of plan selection(5 to 2 days before SRS)
- Target coverage (%) of both plans(5 to 2 days before SRS)
- Minimal radiation dose on target(5 to 2 days before SRS)
- Motor outcome(At 3, 6 and 12 month follow-up)
- tumor recurrence(At 3, 6 and 12 month follow-up)
- Quality of life (EQ-5D-5L)(At 3, 6, and 12 month follow-up)
- Presence of Radiation necrosis(At 12 month follow-up)