Centiloid harmonisation across PET cameras without using paired scan

The Centiloid (CL) scale allows quantification of amyloid‐b accumulation across multiple PET tracers for the diagnosis of Alzheimer’s disease. The CL quantification on different PET cameras may result in significant quantification bias when merging cohorts acquired from multiple cameras or in the longitudinal studies when change of camera occurs. In this study, we propose a harmonisation method, based on the non‐negative matrix factorisation (NMF), to reduce the quantification bias between different cameras without using paired scans.