MR-Linac opens new era for cancer treatment in UK

The Magnetic Resonance Linear Accelerator (MR-Linac) machine, the first in the UK, is housed in a purpose-built suite opened by London mayor Sadiq Khan last November at the Institute of Cancer Research (ICR)’s facility at the west London hospital. The Royal Marsden is a world-leading centre for cancer treatment, and the machine, which will begin treating patients this month, will allow clinicians to target tumours with X-ray radiotherapy with unprecedented accuracy.

MR-Linac combines real-time, moving magnetic resonance imaging with radiotherapy delivery, with a 1.5 Tesla MRI machine and linear accelerators generating X-rays. This allows radiotherapists to watch how X-rays are impinging on the tumour as therapy is delivered.

This is an important innovation, because it allows beam targeting to take account of movement. Internal tumours can move around — albeit generally only by small amounts — under the influence of processes like respiration and the involuntary peristaltic muscular movements of the gastrointestinal system, and the ability to monitor this in real time allows X-rays to be delivered to precisely the right locations. If the tumour margins move out of the path of the converging X-ray beams used to deliver the correct dosage of radiation, they can be stopped, reshaped or repositioned. This minimises the amount of potentially harmful radiation delivered to healthy tissue around the tumour, reducing side-effects and maximising the effectiveness of the treatment.