Axillary Lymph Node Uptake on [.sup.18]F-FDG PET/CT after COVID-19 Vaccination: A Direct Comparison Study with Influenza Vaccination/COVID-19 Asisindan Sonra [.sup.18]F-FDG PET/BT'de Aksiller Lenf Nodu Tutulumu: Grip Asisi ile Dogrudan Karsilastirma Calismasi

Objectives: To compare vaccinated-side axillary lymph node uptake on [.sup.18]F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) after coronavirus disease-2019 (COVID-19) and influenza vaccination. Methods: We retrospectively analyzed 177 patients who underwent [.sup.18]F-FDG PET/CT after COVID-19 or influenza vaccination. We compared the uptake of the vaccinated-side axillary lymph nodes of 109 COVID-19 vaccinated patients with those of a lot of influenza-vaccinated patients. We also compared the uptake between 66 patients who received the first COVID-19 vaccination with 43 who received the second COVID-19 vaccination. Results: [.sup.18]F-FDG-avid axillary lymph nodes on the vaccinated side were significantly more frequently observed in the COVID-19 group (45%) than in the influenza group (19%) (p