Mulder Samuel L, Heukelom Jolien, McDonald Brigid A, Van Dijk Lisanne, Wahid Kareem A, Sanders Keith, Salzillo Travis C, Hemmati Mehdi, Schaefer Andrew, Fuller Clifton D
Department of Radiation Oncology, The University of Texas at MD Anderson Cancer Center, Houston, TX 77030, USA.
Department of Radiation Oncology, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands.
Cancers (Basel). 2022 Apr 10;14(8):1909. doi: 10.3390/cancers14081909.
MR-linac devices offer the potential for advancements in radiotherapy (RT) treatment of head and neck cancer (HNC) by using daily MR imaging performed at the time and setup of treatment delivery. This article aims to present a review of current adaptive RT (ART) methods on MR-Linac devices directed towards the sparing of organs at risk (OAR) and a view of future adaptive techniques seeking to improve the therapeutic ratio. This ratio expresses the relationship between the probability of tumor control and the probability of normal tissue damage and is thus an important conceptual metric of success in the sparing of OARs. Increasing spatial conformity of dose distributions to target volume and OARs is an initial step in achieving therapeutic improvements, followed by the use of imaging and clinical biomarkers to inform the clinical decision-making process in an ART paradigm. Pre-clinical and clinical findings support the incorporation of biomarkers into ART protocols and investment into further research to explore imaging biomarkers by taking advantage of the daily MR imaging workflow. A coherent understanding of this road map for RT in HNC is critical for directing future research efforts related to sparing OARs using image-guided radiotherapy (IGRT).
磁共振直线加速器（MR-linac）设备通过在治疗实施时和设置过程中进行每日磁共振成像，为头颈部癌（HNC）的放射治疗（RT）带来了进步的潜力。本文旨在综述当前针对磁共振直线加速器设备的自适应放射治疗（ART）方法，这些方法旨在保护危及器官（OAR），并展望未来旨在提高治疗比的自适应技术。该比率表示肿瘤控制概率与正常组织损伤概率之间的关系，因此是在保护危及器官方面取得成功的一个重要概念性指标。提高剂量分布与靶体积和危及器官的空间适形性是实现治疗改善的第一步，随后利用成像和临床生物标志物为自适应放射治疗模式下的临床决策过程提供信息。临床前和临床研究结果支持将生物标志物纳入自适应放射治疗方案，并支持利用每日磁共振成像工作流程对进一步探索成像生物标志物的研究进行投入。对头颈部癌放射治疗这一路线图的连贯理解对于指导未来与使用图像引导放射治疗（IGRT）保护危及器官相关的研究工作至关重要。
