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Innovations in radiotherapy practice continue to develop. With the introduction of integrated MRI-guided radiotherapy (MRIgRT) systems, such as hybrid MRI-linear accelerators (MR-linacs), the role of the RTT is changing. There is a need for RTTs to expand their range of tasks and responsibilities, as radiation oncologists and other specialists do not have time to fulfil all tasks that are required in an online setting. For example, RTTs increasingly are involved in online target delineation, online re-planning, and analysis of (functional) MR images.

Daily functional imaging on an MR-linac provides the opportunity to measure changes in tumor biology during treatment. These changes can be used to adapt the treatment, in a process called biological image-guided adaptive radiotherapy (BIGART). We are now at a point where we are collecting data in clinical trials to determine which qMRI parameters change during treatment and assess if those changes are related to clinical outcome with the aim of identifying prognostic qMRI biomarkers.

The implementation of these functional imaging sequences into clinical scan protocols is a collaboration between the RTT and the researchers. The RTT has the practical insight to integrate this in to the workflow as efficiently as possible and the researcher brings the expertise of functional MRI. Together, they determine for each treatment type how much time is available in the adaptation phase and which functional sequences can be added to the MRI protocol on the MR-linac without extending the treatment time for the patient. Also in the analysis of functional MR images there is a role for the RTT, such as delineation of the tumor, calculation of quantitative parameter maps and calculating statistics of these maps.

By involving RTTs in the acquisition and analysis of (functional) MR images, clinical practice and research become connected. This is important to improve research on relevant clinical topics as this will strengthen the clinical relevance of the research and and create a more efficient path from research to clinical implementation.