The collaborative project between engineers at Lancaster University and scientists and clinicians at The University of Manchester, The Christie NHS Foundation Trust and CERN, will develop a prototype ‘X-band linac structure’ that can be retro-fitted on proton beam therapy equipment, which is used in complex radiotherapy treatments at over 50 hospitals around the world.
The technology will enable proton imaging of adults that can help improve the accuracy of proton therapy. Radiotherapy with protons is important in some cancer treatments as its greater treatment accuracy can reduce side effects, for example when treating some cancers in children. While two new NHS proton treatment centers are under construction in the UK that will provide state-of-the-art treatments, the proton imaging based on this prototype will enable the most accurate pre-treatment images of patients, improving on the imaging used today which is based on x-ray imaging.
Proton imaging requires more energetic protons than are used in treatment, and which can pass right through the patient. A very small imaging dose of protons much smaller than that used for treatment—travels through the body region to be imaged; measuring the energy lost on the way allows a picture of that volume to be taken using tomographic techniques. The remaining energy of the protons is measured to find out how much was lost on their way through the body. In this project — ‘PROBE: PROton Beam Extension for Imaging and Therapy’ project—a prototype will be built of a novel high-frequency linac that can boost the energy of protons from the 250 Mega-electron volts (MeV) available from conventional medical cyclotrons to 350 MeV, sufficient for imaging all patients.
Graeme Burt, senior lecturer at Lancaster University’s Engineering Department and lead researcher on the 12-month project, said: “Proton imaging will increase the accuracy of proton treatments to under one millimeter, which really counts when treating tumors near sensitive organs.”
The design of the technology will be tested with the assistance of CERN, which has suitable existing X-band power systems and infrastructure. A successful demonstration will be translated into clinical use for the benefit of patients in the UK and abroad.
Hywel Owen, lecturer at The University of Manchester’s School of Physics and Astronomy and a developer of the booster concept, said: “Whilst detectors for proton imaging are now being developed by several research groups, there is as yet no compact and cost-effective method of providing the 350 MeV protons needed for adults. Bridging this gap is the aim of our project.”
Ranald MacKay, Director of Christie Medical Physics & Engineering, said: “As well as developing a clinical facility to treat 750 patients a year, The Christie Proton Beam Therapy Centre will be a national facility for proton research. This project is a good example of how scientists will work together to improve proton therapy in Manchester.”
The project’s £120,000 costs have been assisted by the project partners and by the national Cockcroft Institute for Accelerator Science and Technology, using an award from the UK Science and Technology Facilities Council (www.stfc.ac.uk).