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

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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.