The Royal Marsden

Why The Royal Marsden used a crab to test the MR Linac

The UK’s first MR Linac performed a ‘beam on image’ research test on a crab to assess the machine’s image quality

The revolutionary machine combines two technologies — an MRI scanner and a state-of-the-art radiotherapy system — to precisely locate tumours and deliver doses of radiation with more accuracy.

It could be especially effective for cancers which move during radiotherapy or change position between scanning and treatment — for instance through breathing, bladder filling or bowel changes.

In order to test the machine’s image quality, researchers at The Royal Marsden and The Institute of Cancer Research scanned a dead crab. They chose a crab as it symbolises cancer in the astrology world and features in The Royal Marsden crest.

Other countries with an MR Linac also scanned iconic objects to test image quality — the first Australian MR Linac imaged a piece of kangaroo meat, while the Netherlands scanned tulips and Texas MD Anderson Cancer Center scanned a T-bone steak.

For us it was interesting to see if the image quality changed when the beam was turned on and when it was turned off. It demonstrated to us that the radiation beam does not affect image quality

Professor Uwe Oelfke Head of the Joint Department of Physics at The Royal Marsden and the ICR

The system is being tested before the first patients are treated later this year, initially through clinical studies in hard-to-treat cancer types.

The UK’s first MR Linac — and fourth in the world — was installed last year at The Royal Marsden and the ICR in Sutton, and was officially opened in November 2016 by Mayor of London Sadiq Khan.