Andreas Wetscherek – CMIC/WEISS joint seminar series

Speaker: Andreas Wetscherek, Institute of Cancer Research (ICR)

Title: Diffusion-weighted imaging and IVIM for MR-guided radiotherapy on an MR-Linac

Abstract: MR-guided radiotherapy on MR-Linacs enables adaptation of the radiotherapy treatment plan to day-to-day changes in anatomy. Replanning is done online while the patient is already in treatment position. To account for physiological motion 4D-MRI can be used to retrospectively reconstruct the delivered dose based on beam-on imaging.

The next frontier in MR-guided radiotherapy is the assessment and prediction of treatment response via functional imaging techniques, such as diffusion-weighted MRI. The aim is to identify resistant and responding treatment volumes at an early stage to facilitate local treatment intensification or de-escalation. While the ADC is often used to assess treatment response, the technique of intra-voxel incoherent motion imaging (IVIM) is also of great interest to assess changes in vasculature without the need for gadolinium-based contrast agents. Challenges and opportunities of DWI in MR-guided radiotherapy are discussed based on the experience at the ICR with the UK’s first MR-Linac.

Bio: During his PhD at the German Cancer Research Center (DKFZ) in Heidelberg, Dr Wetscherek worked on flow-compensated diffusion-weighted MRI. He continued to work as a postdoc at DKFZ developing 4D MR imaging techniques to quantify regional lung motion in fibrotic lung diseases within a multi-disciplinary project connecting medical physics, radiology and medical informatics.

After joining the ICR in 2015, Dr Wetscherek’s research focus shifted towards the applications of MR imaging in radiotherapy, where he led the development of several T2-weighted 4D MR imaging techniques to optimise the visibility of both tumour and radiosensitive risk organs. Since end of 2018 Dr Andreas Wetscherek is leading the Magnetic Resonance Imaging in Radiotherapy Team at ICR focussing on the development of MRI techniques for radiotherapy with particular application to the MR-Linac system, which has been treating patients at the ICR since September 2018. He is interested in characterising day-to-day anatomical variations for treatment adaptation and aims to develop functional imaging techniques to inform cancer therapy by predicting treatment response.