Radiopharmaceuticals to image infection and inflammation

Scintigraphic imaging of infection and inflammation is a powerful diagnostic tool in the management of patients with infectious or inflammatory diseases. Most infectious and inflammatory foci can be visualized accurately with radiolabeled autologous leukocytes. However, the preparation of this radiopharmaceutical is laborious and requires the handling of potentially contaminated blood. A few radiopharmaceuticals are available that could be used instead of radiolabeled leukocytes to scintigraphically visualize infectious and inflammatory foci, such as 67Ga-citrate and 99mTc-labeled antigranulocyte antibody preparations. Various agents labeled with 99mTc are currently developed for this application. Most of these newly developed agents are ligands that bind receptors on white blood cell subpopulations, ie, monoclonal antibodies, chemotactic peptides, and cytokines. Furthermore, agents are developed that potentially could distinguish between infection and nonmicrobial inflammation. In addition, 18F-fluorodeoxyglucose positron emission tomography imaging was proposed to visualize inflammatory foci when a high spatial resolution is required. In this article, the characteristics and diagnostic potential of established and experimental radiopharmaceuticals for infection and inflammation imaging are reviewed.