B cells are key players in the pathogenesis of rheumatoid arthritis (RA). Although successful in 50-60% of patients with RA, anti-B-cell therapy given as rituximab could be more efficient by identifying potential responders prior to treatment. Positron emission tomography (PET) using radiolabeled rituximab for B-cell imaging might provide the means to fulfil this unmet clinical need. The objective of this study was to investigate the association between biodistribution of zirconium-89 (
We included 20 patients with RA who were starting rituximab treatment. At the first intravenous (i.v.) therapeutic dose, patients were also injected with 
PET-positive hand joints (range 1-20) were observed in 18/20 patients. Responders had significantly higher 
Non-invasive B-cell imaging by 