Sequential quantitative MRI for functional characterization of head and neck cancer, outcome prediction and future biological individualization of MRI-guided radiotherapy

随着MRI-LINACS组合的发明和临床实施，使MRI引导的适应性放射治疗、分次放射治疗之前和期间的定量组织特征的顺序评估以及根据预后定量参数的未来个体化、适应性放射治疗成为可能。在实施和测试了头颈部肿瘤特征的最重要的MRI方法，并包括临床研究中的30多名患者，以比较从1.5T MRI-LINAC和现代3T高场MRI上记录的MRI图像数据集获得的信息后，在第一项目阶段，该项目的主要目标如下：除了松弛测量数据和扩散特征外，还将建立进一步的定量方法，主要是血液灌注率，这在最近的动物研究出版物中被描述为治疗结果的相关参数。此外，还计划继续这项已经开始的研究，增加约30名头颈部癌症患者，以建立更好的统计可靠性，并为开发放射治疗结果的预测模型奠定有效的基础。此外，预期收集的患者数据将用于对前一个项目阶段获得的结果进行外部验证。除了在开始治疗前评估的组织特征的初始值外，还将确定放射治疗过程中定量标记物的变化并与结果相关联。这些变化还将用于通知和制定放射治疗过程中剂量分布的功能适应战略，以实现更好的应答率。有希望的定量成像生物标记物以及实现反应自适应核磁共振引导放射治疗的不同技术概念将在使用具有代表性的患者队列的回溯性硅计划研究中进行测试。

With the invention and clinical implementation of combined MRI-Linacs, enabling MRI-guided adaptive radiotherapy, sequential assessment of quantitative tissue characteristics before and during fractionated radiotherapy, as well as future individualised, adaptive radiotherapy according to prognostic quantitative parameters, seems possible. After implementation and testing the most important MRI methods for the characterisation of head and neck tumours and including more than 30 patients in the clinical study for comparing information obtained from MRI image data sets recorded on the 1.5 T MRI-Linac and a modern 3 T high-field MRI in the first project phase, the major aims of this project are now the following: In addition to relaxometric data and diffusion characteristics, further quantitative methods will be established, mainly dealing with blood perfusion, which were described in recent publications on animal studies as relevant parameters for treatment outcome. It is further planned to continue the already started study with about 30 additional head and neck cancer patients to establish a better statistical reliability and a valid basis for the development of prediction models for radiotherapy outcome. Furthermore, the prospectively collected patient data will be used for external validation of the results obtained in the previous project phase. In addition to the initial values of the tissue characteristics assessed before the start treatment, changes in the quantitative markers during the course of radiotherapy will also be determined and correlated with outcome. The changes will also be used to inform and develop strategies for functional adaptation of the dose distribution during the course of radiotherapy in order to achieve better response rates. Promising candidates for quantitative imaging biomarkers as well as different technical concepts to realise response-adaptive MRI–guided radiotherapy will be tested in a retrospective in-silico planning study using a representative patient cohort.