Novel Ga-68-FAPI PET/CT offers oncologic staging without COVID-19 vaccine-related pitfalls

ABSTRACT

Ziel/Aim The global SARS-CoV-2 vaccination campaign brought attention to a recent pitfall in tumor staging by PET/CT. Several publications reported a non-specific F-18-FDG tracer uptake in axillary lymph nodes after COVID-19 vaccination. Ga-68-FAPI PET/CT is a new oncologic imaging tool that may overcome this limitation. Methodik/Methods For this purpose, we compared the tracer uptake in a head-to-head and same-day F-18-FDG and Ga-68-FAPI PET/CT study. 11 patients from our prospective database (NCT04571086) were included showing vaccine-related tracer uptake in axillary lymph nodes up to 6 weeks after COVID- 19 vaccination. Ergebnisse/Results Among the total of 11 patients, all (n = 11) showed visual positive uptake in the lymph nodes ipsilateral to the injection side on F-18-FDG PET. None (n = 0) of the included patients showed significant tracer uptake on Ga-68-FAPI PET. Follow-up imaging confirmed reactive nodal uptake in all patients. The tumor detection efficacy for these patients was 73 % for F-18-FDG and 94 % for Ga-68-FAPI. Schlussfolgerungen/Conclusions In our case series, Ga-68-FAPI demonstrated resistance to vaccine-related pitfalls while presenting superior tumor detection.