[ 99m Tc]Tc-HMPAO-Labeled Leukocyte Imaging of Infection and Inflammation

The identification and localization of infection can be a real challenge. The clinical picture of a skeletal fracture or a vascular graft might raise the suspicion of an infection, but confirming this can be a real diagnostic dilemma. In other cases, the clinical findings may not be localizing, and anatomic imaging modalities might be nondiagnostic. This chapter will review the technical aspects of labeling leukocytes, their biodistribution and radiation dosimetry, and the use of technetium-99m (99mTc)-labeled leukocytes for the identification and/or localization of infection for a variety of clinical scenarios. Gastrointestinal, musculoskeletal, cardiovascular, and pulmonary indications are reviewed, as well as the use in the pediatric population. The advantages and disadvantages of the 99mTc-labeled leukocyte technique are reviewed. Investigational applications and future directions of infection imaging using new radiopharmaceuticals are also discussed.