Radiotherapy is one of the most important anti-cancer treatments and is used to treat around half of all patients in Europe. In radiotherapy, beams of ionising radiation are used to target and kill cancerous cells with a high radiation dose. The more precise this can be done, the higher the survival rates.

Magnetic resonance guided radiotherapy (MRgRT) combines real-time MR images with radiotherapy, providing more detailed images and anatomical information of a patient during treatment than conventional techniques. The simultaneous use of MR images and radiation treatment allows for more precise dose delivery and continuous optimisation of the dose distribution. Even organ or tumour motion, caused by internal movements of the patient (e.g. breathing, swallowing), during treatment can potentially be corrected for, increasing the accuracy of the targeting. This new technique also reduces the side-effects of the treatment, such as destroying healthy tissue and organs, and avoids additional exposure to harmful radiation from diagnostic imaging modalities (e.g. CT) currently in use.

However, both the detectors used for dosimetry and the dose distributions are highly influenced by the magnetic field of the MR (+/- 10%). Traceability for radiation dosimetry and adequate knowledge of detector characteristics are currently lacking, but are needed to allow medical physicists to calibrate the radiation field and to characterise the radiation fields for treatment planning with a known accuracy. Furthermore, methods are needed to assess the accuracy of the Monte Carlo based algorithms for the calculation of detector response and dose distributions in the presence of magnetic fields. In addition, the complexity of treatment devices and treatment workflows continues to increase. Medical physicists need quality assurance procedures to guarantee that the dose distribution is delivered to the patient as intended in treatment planning.

This Joint Research Project focuses on developing new standards and measurement methods for dosimetry and imaging for the safe clinical implementation and application of MRgRT and to support future innovations.

This project is funded by the EMPIR. The EMPIR initiative is co-funded by the European Union’s Horizon 2020 research and innovation programme and the EMPIR  participating states.
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