Inflammation Detector

Positron emission tomography (PET) is a type of medical imaging technique in which radioactive tracers are introduced into the body to allow doctors to detect and measure physiological processes such as inflammation, blood flow and tumour growth. For inflammation, one of the most commonly used tracers is 18F-FDG (fluorodeoxyglucose), but because this tracer labels a variety of metabolically active cells, it lacks specificity. Now, there’s a new tracer in the works: a radioactive version of a natural molecule – Siglec-9 – that binds the inflammatory protein vascular adhesion protein 1. And, the tracer’s greater specificity means it could be used at lower doses and have improved accuracy. Indeed, the hands of the rheumatoid arthritis patient pictured appear to show brighter signals at the inflamed joints when Siglec-9 was used for PET (top) than when 18F-FDG was used (bottom). Such results in early human testing bode well for the tracer’s continued clinical development.

Written by Ruth Williams

Ruth Williams

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Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

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• Image adapted from work by Riikka Viitanen and colleagues
• Turku PET Centre, University of Turku, Turku, Finland
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Journal of Nuclear Medicine, April 2021