The clinical implementation of MR guided therapy (MRgRT) with dedicated MR-integrated radiation devices requires thorough quality assurance (QA) measures (general, patient-specific and workflow) to guarantee that the dose distribution is delivered as intended in treatment planning. Inter- and intra-fractional motion, such as breathing, must be detected and compensated for within adaptive treatment strategies.
When compared to conventional radiotherapy, the technical realisation of the workflow in MRgRT poses significant challenges due to different image contrast, potential magnetic field distortions and interactions of the magnetic field with the radiation field and the dosimetric equipment. Therefore, specific QA tests are required, which include the employment of phantoms and measurements, as well as simulations to estimate the residual uncertainty.
The aim of this work package is to evaluate MR based dose deposition under static and dynamic conditions. This will facilitate the clinical implementation of MRgRT with the development of general-, patient-specific and workflow-QA-tests. General QA procedures include methods to assure the accuracy of the dose delivery and imaging accuracy of the treatment machine. Patient-specific QA procedures aim to prevent malfunctioning of components for the individual patient. Although these measures may assure the accuracy of each single step, end-to-end tests are also necessary to validate the accuracy of the intended workflow. Within these workflow-QA procedures, end-to-end tests in the presence of inter-fraction and intra-fraction organ motion are of special importance.
This working package includes the development of tests to measure and assess, by means of simulations, the overall geometrical as well as dosimetric uncertainties in 2D and 3D within the framework of time-adaptive radiotherapy. All measurement and simulation procedures developed in this work package will be vendor-independent with respect to the MR-integrated irradiation device.