Medical imaging and therapy
The Nuclear and Hadron Physics group are looking at new ways to analyse Positron Emission Tomography (PET) data. Working alongside the leading radiation detector development company Kromek Group plc, our approach involves making use of signals that can be recorded by PET machines, but are not presently utilised in image reconstructions. The new approach under development promises to improve the sharpness and contrast of PET images, giving rise to significant cost benefits. It is foreseen that better and faster imaging will be achieved which in turn would lead to more appropriate treatments, fewer futile surgical interventions, and improved therapy choices of the increasingly expensive chemotherapies applied by oncologists. We are also developing new techniques and methods that allow the evolution of compact gamma sources (CgS) based on laser-plasma acceleration. This rapidly evolving technology will greatly reduce the size, cost, and staffing necessary for the operation of gamma beams in medicine and industrial applications, including radiotherapy, medical imaging, homeland security and materials science.
PET: In PET imaging a patient is injected with sugar substance containing a radioactive atom, usually fluorine. When this atom decays, two photons are emitted in opposite directions. By detecting many of these two photon events, an image of the source can be reconstructed. PET imaging is used for many important clinical diagnoses such as identifying cancerous tissue and diagnosing Alzheimer’s.
The noise created by false coincidences in PET (for example the detection of two photons not originating from the same event) limits the rate of activity of the radioactive source that can be given to patients. This means that it typically takes about 30 minutes to acquire the volume of data required to create an image with sufficient spatial resolution to carry out diagnoses.
Reducing the time required to perform a scan would mean that more patients could be scanned on the same machine each day thus bringing down the cost per patient.
The new method being investigated utilises physical processes that photons undergo in a way that is not currently made use of in PET imaging, but is applied in nuclear physics research. The bulk of work is being done using Monte Carlo simulations under the Geant4 and GATE frameworks. A prototype PET detector system is also being developed in the lab alongside our industrial partner Kromek group plc.
CgS: Compact, pulsed high-energy gamma sources (CgS) have the potential to revolutionise radiotherapy. The short pulses produced by CgS destroy cancerous cells preferentially to healthy cells, whereas continuous beams show no distinction. In addition, CgS have the capability to significantly reduce the unwanted radiation dose to the patient delivered from neutron-producing reactions, as well as the capability to produce tunable mono-energetic gamma-beams. There is genuinely exciting potential to realise these opportunities to improve the clinical outcome for radiotherapy patients.
Currently there is no technology capable of characterising and identifying the high-energy gammas produced by compact accelerator sources. Even state-of-the-art fast gamma detectors, with very high (and costly) segmentation are overwhelmed by the instantaneous event rate produced by the ultra-short duration (femtosecond) pulses produced, hindering the development and commercialisation of compact gamma beams. We are developing a new prototype detector based on concepts and techniques from nuclear physics, which would allow characterisation of high-energy gamma beams from compact sources.