In November 2016 the Mayor of London Sadiq Khan unveiled the UK’s first revolutionary MR Linac machine at London’s Royal Marsden hospital. This IGRT (Image Guided Radiotherapy) machine has been developed by The Royal Marsden, the ICR (Institute of Cancer Research) and human care company Elekta and is due to treat its first patients in the second half of 2017 following a program of testing.
The installation of this technology at The Royal Marsden has required a specially built bunker into which a four tonne magnet and other sections had to be lowered through a skylight. The Royal Marsden is one of only a handful of international centres to have a MR Linac machine and its scientists were key players in the technology’s development. Funding to the tune of £10 million was provided through a grant from the Medical Research Council.
What are the current issues with radiotherapy?
Radiotherapy is the use of high-energy radiation against cancer cells or other growths. This treatment works because the radiation damages the DNA in the cancer cells causing them to die. Healthy tissues that surround the cancer are also at risk from radiotherapy but these cells usually manage to repair any DNA damage done.
Precise radiotherapy treatment relies on the ability to direct radiation accurately at the tumour. This is very difficult when neither of the elements (the tumour nor the radiation) can be seen. Tumours change in size and position, for example a prostate tumour can move according to the state of the patient’s bowels and a lung tumour will move as the patient breathes. Tumours can move around during treatment. At present scans to ensure tumour position are taken before treatment and treatment relies on complex delivery systems. Current x-ray technology is not capable of discerning between different types of soft tissue to an accurate enough degree to guarantee radiation accuracy. This means that surrounding tissue will suffer damage and that the patient will require a higher dose of radiation than would be needed with more accurate direction.
What is the MR Linac?
The MR Linac is an example of Image Guided Radiotherapy IGRT. It combines MRI (Magnetic Resonance Imaging) technology, which accurately locates tumours, with powerful linear accelerators, which deliver the high-energy x-ray beams, providing doctors with the ability to direct highly accurate treatment. The combination of MR and x-ray has previously presented significant scientific challenge as the magnetic field used to generate MR images has a distorting effect. The development of MR Linac is the result of many years of research.
How does the MR Linac work?
According to Elekta, the MR Linac combines three state-of-the-art systems:
- A high-field MR (Magnetic Resonance) system, which allows for the accurate visualisation of healthy and cancerous soft tissue during treatment, whilst providing imaging that can be used to pull together information on tissue biology.
- A digital linear accelerator, which moves around a continuous rotation gantry and can deliver advanced radiotherapy techniques through the MRI inner ring.
- Advanced software enhancements, which, amongst other things, will allow for accurate image release during treatment, manage motion in new and exciting ways and facilitate dynamic in-treatment planning.
What are the benefits of MR Linac?
- To enable doctors to direct radiotherapy in a very precise manner, minimising healthy tissue damage and radiation doses.
- To enable the capture of images throughout treatment to ensure on going treatment accuracy.
- To reduce unpleasant side effects.
- To increase chances of a cure.
When will MR Linac be available in the UK?
Since its installation in 2016 the MR Linac machine has been undergoing a rigorous series of tests. It is due to be used to treat patients for the first time during the second half of 2017. Initial treatments will be for patients with cancers that are particularly hard to treat.
The MR Linac represents a significant and exciting move forward in the use of radiotherapy to treat cancer. It represents the opportunity to significantly improve the prognosis of cancer patients whilst reducing the unpleasant side effects that can have an impact on patient progress. This is a state-of-the-art technology and will be central to the London Cancer Hub, which aims to speed up the discovery of new treatments by bringing thousands of scientists together.