New proton imaging technology could improve cancer treatments

Researchers at Lancaster and Manchester Universities, the Christie NHS Foundation Trust and CERN are developing the technique, known as proton imaging.

The technology is designed to improve the accuracy of images taken of adults being targeted with proton beam therapy, an emerging technique that can reduce the side effects of complex radiotherapy treatment.

Two new NHS proton treatment centres are already under construction in the UK, and the researchers hope the new technique will produce more accurate pre-treatment images of patients than existing x-ray scans.

Proton imaging can increase the accuracy of treatments down to under one millimetre, which is particularly important when the tumour is near a sensitive organ, according to Dr Graeme Burt of Lancaster University, the lead researcher on the project.

The technique works by firing a very small dose of imaging protons at the patient. These protons, which are more energetic than those used in therapy, travel right through the body, losing some energy as they go, according to Dr Hywel Owen, project member and lecturer at Manchester University.

“The protons slow down as they pass through the body, so if you measure how much energy they had before they went through the body, and how much energy they have afterwards, you can work out how much they have lost,” he said.

These measurements are used to produce a 3D picture of the tissue, he said. “If you add up lots of individual measurements from all of the protons travelling in different directions, then you can build up a tomograph, which gives you a 3D picture of what’s inside the patient.”

The researchers will develop a prototype device, which can be retrofitted onto existing proton beam therapy equipment. This will boost the energy of the protons from the 250 Mega-electron volts (MeV) needed for therapy to the 350MeV needed for full body imaging, said Burt.

“We generate the extra 100MeV needed for full body imaging, and in a space small enough to fit into the proton therapy centres at UCL and at Christie, which are already under construction,” he said.

The researchers will begin manufacturing their prototype booster this summer, and plan to test it at CERN within the next 12 months.

The project is being funded by the Cockcroft Institute for Accelerator Science and Technology, using an award from the UK Science and Technology Facilities Council.