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Increased 18F-FDG Uptake in the Axillary Lymph Nodes of the Vaccinated Side Associated with COVID-19 Vaccination


  • Yoichi Otomi
  • Saho Irahara
  • Hiroaki Inoue
  • Takayoshi Shinya
  • Hideki Otsuka
  • Masafumi Harada

Received Date: 02.04.2021 Accepted Date: 12.05.2021 Mol Imaging Radionucl Ther 2022;31(2):169-171 PMID: 35771098

A 50-year-old female patient underwent (18fluorine-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) following modified radical mastectomy for cancer of the left breast. Ten days before the PET/CT, the coronavirus disease-2019 (COVID-19) vaccine was injected intramuscularly into the right deltoid muscle. Increased (18F-FDG uptake of maximum standardized uptake value (11.0) was observed in the lymph nodes of the right axilla, which had not been observed in the previous PET/CT. The size of the oval-shaped lymph nodes was up to approximately 11×9 mm; however, it was larger than that observed on the previous PET/CT. We contemplate that the increased (18F-FDG uptake was a reactive change in the lymph nodes associated with the COVID-19 vaccine.

Keywords: COVID-19, vaccination, 18F-FDG PET/CT


Informed Consent: Written informed consent of the patient was obtained.

Peer-review: Externally peer-reviewed.

Authorship Contributions

Surgical and Medical Practices: Y.O., S.I., H.I., Concept: Y.O., S.I., Design: Y.O., S.I., Data Collection or Processing: Y.O., S.I., H.I., Analysis or Interpretation: Y.O., T.S., H.O., M.H., Literature Search: Y.O., S.I., Writing: Y.O.

Conflict of Interest: No conflict of interest was declared by the authors.

Financial Disclosure: The authors declared that this study received no financial support.


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