Radiation therapy (RT) plays a vital role in the treatment of brain cancers, but it frequently results in cognitive decline in the patients who receive it. Because the underlying mechanisms for this decline remain poorly understood, the brain is typically treated as a single, uniform volume when evaluating the toxic effects of RT plans. This ignorance represents a significant deficit in the field of radiation oncology, as the technology exists to manipulate dose distributions to spare regions of the brain, but there exists no body of knowledge regarding what is critical to spare. This deficit exists due to the numerous confounding factors that are frequently associated with radiotherapy, including the tumors themselves, other treatments such as surgery and chemotherapy, and dose gradients across the brain. Here, we present a case in which a 57-year-old male patient received a uniform dose of radiation across the whole brain, did not receive concurrent chemotherapy, had minimal surgical intervention and a small tumor burden, and received resting-state functional magnetic resonance imaging (fMRI) scans both before and after RT. To our knowledge, this is the first study on the effects of whole-brain radiotherapy on functional network organization, and this patient's treatment regimen represents a rare and non-replicable opportunity to isolate the effects of radiation on functional connectivity. We observed substantial changes in the subject's behavior and functional network organization over a 12-month timeframe. Interestingly, the homogenous radiation dose to the brain had a heterogeneous effect on cortical networks, and the functional networks most affected correspond with observed cognitive behavioral deficits. This novel study suggests that the cognitive decline that occurs after whole-brain radiation therapy may be network specific and related to the disruption of large-scale distributed functional systems, and it indicates that fMRI is a promising avenue of study for optimizing cognitive outcomes after RT.

中文翻译：

---

全脑放射治疗后人脑功能网络组织受到破坏。

放射疗法（RT）在脑癌的治疗中起着至关重要的作用，但是它经常导致接受放射疗法的患者认知能力下降。由于这种下降的潜在机制仍然知之甚少，因此在评估RT计划的毒性影响时，通常将大脑视为单个均匀的体积。由于存在操纵剂量分布到大脑备用区域的技术，这种无知代表了放射肿瘤学领域的重大缺陷，但是对于备用至关重要的知识却不存在。这种缺陷的存在是由于经常与放疗相关的众多混杂因素，包括肿瘤本身，其他疗法（例如手术和化学疗法）以及整个大脑的剂量梯度。这里，我们介绍了一个案例，其中一名57岁的男性患者在整个脑部接受统一剂量的辐射，未同时接受化学疗法，手术干预最少，肿瘤负担小，并且接受了静息状态功能磁共振成像（fMRI）在RT之前和之后进行扫描。据我们所知，这是关于全脑放射治疗对功能网络组织影响的首次研究，该患者的治疗方案代表了一个难得且不可重复的机会，可以将放射线对功能连接的影响隔离开来。我们观察到在12个月的时间内受试者的行为和功能网络组织发生了重大变化。有趣的是，对大脑的均匀辐射剂量对皮层网络具有不同的影响，受影响最大的功能网络与观察到的认知行为缺陷相对应。这项新颖的研究表明，全脑放射治疗后发生的认知能力下降可能是网络特异性的，并且与大规模分布式功能系统的破坏有关，并且表明功能磁共振成像是优化RT后认知结果的有前途的研究途径。