Medical applications of opaque scintillator radiation detectors

点击翻译按钮获取中文摘要

This project is to develop a novel radiation detector technology for medical imaging that will allow devices with substantially improved performance to be built in a more cost-effective way. In medicine radioactive tracers are routinely injected into the blood stream for imaging purposes. The most commonly used one is based on glucose, which is preferentially taken up by cancer tumours or other active parts of the body thus concentrating the radioactivity. Radioisotopes that decay by emitting positrons are used since the annihilation with electrons gives rise to two 0.51 MeV gamma rays that are emitted in opposite directions (back-to-back) and typically escape from the body. Images can be formed by recording the positions and times of the gammas from thousands, or even millions, of radioactive decays. This is the technique used in a Positron Emission Tomography (PET) scanner. These scanners are growing in demand yet their high price (typically £1.5 million per scanner) is a factor that limits their availability. The scintillation crystals used to detect the gamma rays are a substantial fraction of the cost. The objective of this project is to develop a new opaque scintillator detector that will allow larger, higher performance scanners to be built in a more cost-effective way.Many radiation detectors use scintillators, which are materials that give off light when radiation such as gamma rays hits them. Traditionally, scintillators have always been transparent, and this was necessary to allow detection of the light. The new concept that will be applied in this project is to use the combination of an opaque scintillator and a lattice of fibre optic cables. The opacity causes the light to bounce around close to where it is produced and then the fibres extract the light. Such a configuration enables high-resolution imaging capabilities at a lower cost. In the first half of this project we will investigate multiple scintillators in opaque form to establish their performance in combination with different configurations of wavelength shifting fibre optic cables. The results from those investigations will inform our design of a prototype radiation detector for medical imaging that will be built in the second half of the project.