(Credit: Maximilien Brice/CERN)
A multidisciplinary consortium has created one of the most complex medical imaging devices ever conceived, allowing real-time monitoring of the radiation dosage being given to cancer patients using proton therapy. The work will also improve treatment verification and planning, based on images from proton computed tomography (pCT), greatly reducing errors in tumour targeting.
There are over 300,000 new cases of cancer diagnosed in the UK every year. Of those around 4 out of 10 people will have radiotherapy as part of their treatment. Annual NHS costs for cancer services are £5 billion, but the cost to society as a whole, including costs for loss of productivity, is £18.3 billion. Recent advances in cancer treatment have seen the use of proton particles as an alternative to x-rays. To improve the treatment of cancer, the UK government have committed to building two new dedicated proton beam therapy centres at The Christie Hospital in Manchester and University College London Hospital NHS Foundation Trust.
Proton therapy enables a lower radiation dose to a patient receiving radiotherapy (compared to x-rays) and allows more accurate targeting of the tumour. Like x-rays, protons can penetrate tissue to reach deep tumours. However, compared to x-rays, protons cause less damage to healthy tissue in front of the tumour, and no damage at all to healthy tissue lying behind, greatly reducing the side effects of radiation therapy.
Using technology originally developed for the High Luminosity-Large Hadron Collider (HL-LHC), members of the Proton Radiotherapy Verification and Dosimetry Applications (PRaVDA) consortium helped overcome obstacles associated with proton beam therapy. Proton therapy is more sensitive than conventional x-ray treatment to uncertainties in both treatment planning and delivery.
The Large Hadron Collider (LHC) is the world’s largest and most powerful particle accelerator, it lets scientists reproduce the conditions that existed within a billionth of a second after the Big Bang.
HL-LHC is the planned upgrade to the LHC that will allow the accelerator to provide more accurate measurements of new particles and enable observation of rare processes, making it possible to detect rare events not previously witnessed.
PRaVDA consisted of a team of leading instrumentation engineers and scientists, medical, high-energy and nuclear physicists and oncologists from across the UK and South Africa. Institutions involved from the UK include the Universities of Birmingham, Lincoln, Liverpool, Warwick and Surrey, University Hospital Coventry and Warwickshire NHS Trust and the University Hospital Birmingham NHS Foundation Trust. The consortium worked with UK industry in the manufacturing of hardware for the device; this includes Micron Semiconductor (UK) Ltd, Image Sensor Design and Innovation (ISDI) and Express Circuits Group Ltd. This demonstrates the skills and knowledge UK industry has to be able to provide unique components for pioneering instruments.
The instrument originally developed by PRaVDA is a tracking detector which allows the user to predict the path of a particle very accurately as it passes through space. The instrument will also measure the loss of energy and scattering of protons as they pass through a patient. This means a 3D image of the tumour can be created using the same beam that is also used to treat the tumour.
Clinicians will be able to better predict the energy level and location of the dose, allowing treatment to be altered to ensure the tumour is being hit, rather than the surrounding healthy tissue. This is particularly important in vulnerable parts of the body such as the brain, eye and spinal cord.
The instrument is seen as ideal to treat cancer in children, reducing the risk of secondary cancers that can appear many years later in a patient’s life. This has particular social and economic benefits as the patients long-term health is improved and reduces the chance of more cancer treatment being needed.
Alongside support from STFC, PRaVDA received funding from the Wellcome Trust to develop the instrument based on technology for the upgrade programme at the LHC. STFC is continuing to support this area of technology development with an award of just under £1million for the Global Challenge Network+ in Advanced Radiotherapy.
The scanner is now being developed by the OPTIma (Optimising Proton Therapy through Imaging) project, funded by a £3.3 million grant from the Engineering and Physical Sciences Research Council (EPSRC). It will be part of the research room at the Christie Hospital in Manchester, and will be the first time that a proton imaging system is installed in an operational proton therapy centre.
Last updated: 30 October 2018