Next-generation image-guided radiotherapy delivery system
MR-Linac is an exciting technology that combines highly precise imaging and a radiotherapy delivery system that allows for real-time imaging with soft tissue definition superior to that of current standard of care systems. The integrated treatment planning system facilitates real-time treatment adaptations and has the potential to integrate functional imaging (i.e. information about tumour and normal tissue physiology/changes) directly into the radiotherapy pathway.
By being able to see more we can learn more about how tumours and normal tissues change in real time. That is how the treatment is impacting each patient, and the ability to personalise treatment on a schedule specific to his/her needs. As patients change anatomy on various different timescales, from short-term (for example changes in bowel motion and bladder filling) to longer-term (for example weight-loss) regular imaging is useful to enable the treatment to be adapted due to these changes, whilst some tumours change over time through shrinkage as a result of radiotherapy.
A daily personalised treatment plan takes account of the size and shape of the cancer, the surrounding normal tissue and monitoring the movement of internal organs. This enables healthy tissue to be given less dose which reduces side effects and may soon allow us to give more dose to the tumour to further increase the chance of survival.
Building the MR-Linac
Installation of the MR-Linac began in 2016 and began being used for patient treatments in May 2019, making The Christie only the second site in the UK and sixth in the world to deliver treatments with this incredible machine. Currently, the team has implemented MR-Linac to treat prostate cancer using different adaptation methods as well as implemented stereotactic ablative body radiotherapy (SABR) treatments for this treatment site in July 2020.
Every patient treated on this system is enrolled into a clinical trial so more can be learned about the impact of radiotherapy, how to make radiotherapy more personalised and kinder (i.e. fewer toxicities) in hard to treat tumours. Most importantly – through the use of patient experience surveys – the team are actively engaging the patient in research developments.
The cross-discipline MR-Linac group work with all the professional groups fully engaged in exploring how this technology can be used to improve patient outcomes. In addition, the team collaborate nationally and internationally with other MR-Linac groups – for example within the MRL Consortium, alongside The Royal Marsden Hospital, and University of Oxford.
The team are working with industry to develop novel automated tools to make treatments more efficient and we are training future radiotherapy/radiation oncology professionals both in clinical and academic practice.
Professor Ananya Choudhury is one of the leading radiotherapy researchers in Manchester. In this Cancer Futures article, Ananya talks about the pioneering treatment offered using the MR-Linac technology, and what it means for patients.
The machine is a focal point for a large amount of active research. This research includes work to:
- Improve the efficiency of the treatment so that patients don’t have to lie on the treatment couch so long and so more patients can be treated.
- Using special MRI sequences that can see functional changes not just anatomical changes and machine learning to improve various parts of the treatment workflow.
- Various treatment planning studies have been performed by the group to investigate the effect of the magnetic field on treatments.
The team also intends to use the true power of the MR-Linac by moving beyond daily adaptive to functionally guided radiotherapy by, for example, developing oxygen enhanced MR research. The aim is to incorporate this into the treatment workflow. All the group’s work aims to optimise treatment to improve the targeting of tumours whilst sparing surrounding healthy tissue.
The increased use of SABR on the machine is expected to deliver patient benefit with fewer, higher dose treatments required. The improved imaging of the MR-Linac should enable more of these treatments to be implemented, including the aim to treat abdominal tumours, such as pancreatic and liver cancers. These tumour sites suffer a very poor prognosis but initial research indicates that the MR-Linac could improve outcomes.