MRI can help to categorize tissues as malignant or non-malignant both anatomically and functionally, with a high level of spatial and temporal resolution. This non-invasive imaging modality has been integrated with radiotherapy in devices that can differentially target the most aggressive and resistant regions of tumours. The past decade has seen the clinical deployment of treatment devices that combine imaging with targeted irradiation, making the aspiration of integrated MRI-guided radiotherapy (MRIgRT) a reality. The two main clinical drivers for the adoption of MRIgRT are the ability to image anatomical changes that occur before and during treatment in order to adapt the treatment approach, and to image and target the biological features of each tumour. Using motion management and biological targeting, the radiation dose delivered to the tumour can be adjusted during treatment to improve the probability of tumour control, while simultaneously reducing the radiation delivered to non-malignant tissues, thereby reducing the risk of treatment-related toxicities. The benefits of this approach are expected to increase survival and quality of life. In this Review, we describe the current state of MRIgRT, and the opportunities and challenges of this new radiotherapy approach.

MRI 可以帮助从解剖学和功能上将组织分类为恶性或非恶性，并具有高水平的空间和时间分辨率。这种非侵入性成像方式已与设备中的放射治疗相结合，可以有区别地针对肿瘤最具侵袭性和耐药性的区域。在过去的十年里，结合成像和靶向照射的治疗设备在临床上得到了部署，使综合 MRI 引导放射治疗 (MRIgRT) 的愿望成为现实。采用 MRIgRT 的两个主要临床驱动力是能够对治疗前和治疗期间发生的解剖变化进行成像，以适应治疗方法，并对每个肿瘤的生物学特征进行成像和定位。利用运动管理和生物靶向，可以在治疗过程中调整输送到肿瘤的辐射剂量，以提高肿瘤控制的可能性，同时减少输送到非恶性组织的辐射，从而降低治疗相关毒性的风险。这种方法的好处预计将提高生存率和生活质量。在这篇综述中，我们描述了 MRIgRT 的现状，以及这种新放射治疗方法的机遇和挑战。