It’s vital that these variations aren’t caused by differences in the machines themselves or by differences in local scanning practice – that would potentially compromise future clinical trials. This is why the DPUK programme has taken so much care to ensure that each scanner in the network is set up to the same highest standards for research.
PET phantom testing
With the five new scanners installed, researchers needed to establish the ability of each scanner to measure radioactivity distributions. They’re not the same and scientists have used a complex set of measurements to evaluate each scanner’s performance. The work involved working with specially designed objects called PET phantoms which measure how each scanner can measure areas of uniformity and contrast.
Characterising the scanners like this is particularly important for interpreting differences in human brain scans – for example the distribution of amyloid-beta – a protein that is known to be involved in Alzheimer’s disease. The key aspect of phantoms is that we do know the underlying true distribution of the radioactivity used in the testing, whereas for real brain scans we do not know it. When the team conducted this testing phase they could establish that scanner measurements were accurate and there were no significant interference or quantification errors. This is the first step in giving the scientists and trial managers the reassurance they need for future drug trials and experimental studies.
Using people to test scanners
In clinical trials for new drug treatments for dementia, researchers will use the DPUK scanners to test people. But before that – to give trial managers confidence and reassurance in the quality and validity of the images – the DPUK team needs to use people to do the final tests of the scanners. This is because there are important aspects that cannot be assessed using PET phantoms. This critical next phase will demonstrate how the scanners are working. It will give future users of the scanners – trial managers, imagers, researchers – a very high degree of reassurance that the methods and technology used for brain imaging across the UK are rock solid and are at the highest standards in the field.