UK’s first MR Linac, combining MRI and radiotherapy technology

The first MR linac to be commissioned in the UK is starting to be used to treat patients.

The benefit of the Elekta Unity magnetic resonance radiation therapy (MR/RT) linac is that it precisely locates tumours, tailors the shape of high energy x-ray beams following real time adaptation of the dosimetric plan and accurately delivers radiation.

Combining the precise soft-tissue contrast of MRI scanning (1.5 Tesla) with precision radiotherapy in a single treatment technology has been an aspiration for radiotherapy research. A stringent physics commissioning programme has demonstrated that the MR linac can be calibrated to deliver x-rays accurately in the presence of the distorting magnetic field used to generate MRI images.

In doing so, researchers have overcome a key scientific challenge. This technology could be especially effective for cancers which move during radiotherapy or change position between scanning and treatment. For example, because of breathing, bladder filling or bowel changes. This is particularly useful for radiotherapy for lung, cervical, prostate, bowel and bladder cancer.

It also could support significant reductions in overall number of treatments as radiotherapy moves towards increasing use of stereotactic ablation treatments..

"This really is ground-breaking technology which will provide enormous benefits for patients and their families," Sarah Helyer, radiotherapy services manager, at The Royal Marsden, said.

"Having one of the first MR linacs in the UK at the Marsden has brought together all the main professions in radiotherapy, working as a team to bring this technology into the clinic." Sarah continued.

“This is especially good for therapeutic radiographers, who have worked alongside their diagnostic colleagues, to gain the skills and experience necessary to take on MRI technology in radiotherapy in the future.”

Dr Alison Tree, a consultant oncologist, explained the impact for prostate cancer patients: “Prostate cancer responds most effectively to large doses of radiation delivered over a short period. However, because the prostate lies close to the rectum, high doses risk damaging the rectum and increasing side effects.

“With the MR linac we can better target treatment, so we can safely deliver higher doses of radiation. Treatment time could be reduced to five days, or even just one, which will save time and money for patients and the NHS.”

The Royal Marsden and the Institute of Cancer Research have been developing the technology for several years as part of an international consortium of seven cancer treatment centres working with Elekta, which makes the MR linac, and MR partner Phillips.

The first patient
Barry Dolling from Surrey: “I was diagnosed with prostate cancer in April this year. I was told about the clinical trial on the MR linac when I was referred to The Royal Marsden for radiotherapy. I jumped at the chance because I believe the treatment will give me a better quality of life and minimal side effects in comparison to other treatments.

"I will be having 20 treatments on the MR linac and Iam hoping to keep up with my swimming and golf. It was important to me to have treatment that had minimal side effects. I am lucky the timings worked out for me as the trial just opened at the time I would have been starting standard radiotherapy treatment. I was really excited when they told me I would be the first patient in the UK. I feel very privileged.”

Source: sor.org