Nuclear Medicine plays an important role in the evaluation of patients suspected of harboring infection. Gallium imaging is especially useful for opportunistic infections and spinal osteomyelitis. In vitro labeled leukocyte imaging is the current radionuclide gold standard for imaging most infections, in immunocompetent patients, including cardiovascular, postoperative, and musculoskeletal infections (except spinal osteomyelitis). Several in-vivo leukocyte labeling methods have been investigated, but none are widely used. Results obtained with radiolabeled antibiotics have been disappointing. Data on FDG are still emerging, but this agent appears to be especially valuable in fever of unknown origin, spinal osteomyelitis, vasculitis and sarcoidosis. It is conceivable that in the near future, FDG-PET and PET/CT will replace gallium for many indications. Investigators also are studying ways to label leukocytes with positron emitters in order to combine the advantages of PET with those of labeled leukocytes.
Infection; labeled leukocytes; gallium; FDG; PET